wxWidgets/samples/opengl/pyramid/oglstuff.cpp

1264 lines
41 KiB
C++

/////////////////////////////////////////////////////////////////////////////
// Name: oglstuff.cpp
// Purpose: OpenGL manager for pyramid sample
// Author: Manuel Martin
// Created: 2015/01/31
// Copyright: (c) 2015 Manuel Martin
// Licence: wxWindows licence
/////////////////////////////////////////////////////////////////////////////
#include <cmath>
#include "oglstuff.h"
// External function for GL errors
myOGLErrHandler* externalMyOGLErrHandler = NULL;
// Allow GL errors to be handled in other part of the app.
bool MyOnGLError(int err, const GLchar* glMsg = NULL)
{
GLenum GLErrorVal = glGetError();
if ( err == myoglERR_CLEAR )
{
// Clear previous errors
while ( GLErrorVal != GL_NO_ERROR )
GLErrorVal = glGetError();
return true;
}
if ( (GLErrorVal == GL_NO_ERROR) && (glMsg == NULL) )
return true;
if ( externalMyOGLErrHandler )
{
// Use the external error message handler. We pass our err-enum value.
externalMyOGLErrHandler(err, GLErrorVal, glMsg);
}
return err == myoglERR_JUSTLOG ? true : false;
}
// We do calculations with 'doubles'. We pass 'GLFloats' to the shaders
// because OGL added 'doubles' since OGL 4.0, and this sample is for 3.2
// Due to asynchronous nature of OGL, we can't trust in the passed matrix
// to be stored by GPU before the passing-function returns. So we don't use
// temporary storage, but dedicated matrices
void SetAsGLFloat4x4(double *matD, GLfloat *matF, int msize)
{
for (int i = 0; i < msize; i++)
{
matF[i] = (GLfloat) matD[i];
}
}
// ----------------------------------------------------------------------------
// Data for a regular tetrahedron with edge length 200, centered at the origin
// ----------------------------------------------------------------------------
const GLfloat gVerts[] = { 100.0f, -40.8248f, -57.7350f,
0.0f, -40.8248f, 115.4704f,
-100.0f, -40.8248f, -57.7350f,
0.0f, 122.4745f, 0.0f };
// Transparency (to see also inner faces) is in the last triangle only,
// so that glEnable(GL_BLEND) works well
const GLfloat gColours[] = { 0.0f, 1.0f, 0.0f, 1.0f,
1.0f, 0.0f, 0.0f, 1.0f,
0.0f, 0.0f, 1.0f, 1.0f,
1.0f, 1.0f, 0.0f, 0.3f }; //With transparency
// Normals heading outside of the tetrahedron
const GLfloat gNormals[] = { 0.0f, -1.0f, 0.0f, /* face 0 1 2 */
-0.81650f, 0.33333f, 0.47140f, /* face 1 2 3 */
0.0f, 0.33333f, -0.94281f, /* face 2 3 0 */
0.81650f, 0.33333f, 0.47140f /* face 3 0 1 */ };
// Order would be important if we were using face culling
const GLushort gIndices[] = { 0, 1, 2, 3, 0, 1 };
// ----------------------------------------------------------------------------
// Shaders
// ----------------------------------------------------------------------------
// Note: We use GLSL 1.50 which is the minimum starting with OpenGL >= 3.2 (2009)
// Apple supports OpenGL 3.2 since OS X 10.7 "Lion" (2011)
// Vertex shader for the triangles
const GLchar* triangVertexShader =
{
"#version 150 \n"
"in vec3 in_Position; \n"
"in vec4 in_Colour; \n"
"in vec3 in_Normal; \n"
"uniform mat4 mMVP; \n"
"uniform mat4 mToViewSpace; \n"
"flat out vec4 theColour; \n"
"flat out vec3 theNormal; \n"
"out vec3 pointPos; \n"
"void main(void) \n"
"{\n"
" gl_Position = mMVP * vec4(in_Position, 1.0); \n"
" theColour = in_Colour; \n"
" // Operations in View Space \n"
" vec4 temp4 = mToViewSpace * vec4(in_Position, 1.0); \n"
" pointPos = temp4.xyz; \n"
" temp4 = mToViewSpace * vec4(in_Normal, 0.0); \n"
" theNormal = normalize(temp4.xyz); \n"
"}\n"
};
// Common function for fragment shaders
const GLchar* illuminationShader =
{
"#version 150 \n"
"vec3 Illuminate(in vec4 LiProps, in vec3 LiColour, in vec4 PColour, \n"
" in vec3 PNormal, in vec3 PPos) \n"
"{\n"
" // Ambient illumination. Hardcoded \n"
" vec3 liAmbient = vec3(0.2, 0.2, 0.2); \n"
" // Operations in View Space \n"
" vec3 lightDirec = LiProps.xyz - PPos; \n"
" float lightDist = length(lightDirec); \n"
" // Normalize. Attention: No lightDist > 0 check \n"
" lightDirec = lightDirec / lightDist; \n"
" // Attenuation. Hardcoded for this sample distances \n"
" float attenu = 260.0 / lightDist; \n"
" attenu = attenu * attenu; \n"
" // Lambertian diffuse illumination \n"
" float diffuse = dot(lightDirec, PNormal); \n"
" diffuse = max(0.0, diffuse); \n"
" vec3 liDiffuse = LiColour * LiProps.w * diffuse * attenu; \n"
" // Gaussian specular illumination. Harcoded values again \n"
" // We avoid it for interior faces \n"
" vec3 viewDir = vec3(0.0, 0.0, 1.0); \n"
" vec3 halfDir = normalize(lightDirec + viewDir); \n"
" float angleHalf = acos(dot(halfDir, PNormal)); \n"
" float exponent = angleHalf / 0.05; \n"
" float specular = 0.0; \n"
" if (diffuse > 0.0) \n"
" specular = exp(-exponent * exponent); \n"
" vec3 lightRes = PColour.rgb * ( liAmbient + liDiffuse ); \n"
" // Specular colour is quite similar as light colour \n"
" lightRes += (0.2 * PColour.xyz + 0.8 * LiColour) * specular * attenu; \n"
" lightRes = clamp(lightRes, 0.0, 1.0); \n"
" return lightRes; \n"
"}\n"
};
// Fragment shader for the triangles
const GLchar* triangFragmentShader =
{
"#version 150 \n"
"uniform vec4 lightProps; // Position in View space, and intensity \n"
"uniform vec3 lightColour; \n"
"flat in vec4 theColour; \n"
"flat in vec3 theNormal; \n"
"in vec3 pointPos; \n"
"out vec4 fragColour; \n"
"// Declare this function \n"
"vec3 Illuminate(in vec4 LiProps, in vec3 LiColour, in vec4 PColour, \n"
" in vec3 PNormal, in vec3 PPos); \n"
"void main(void) \n"
"{\n"
" vec3 lightRes = Illuminate(lightProps, lightColour, theColour, \n"
" theNormal, pointPos); \n "
" fragColour = vec4(lightRes, theColour.a); \n"
"}\n"
};
// Vertex shader for strings (textures) with illumination
const GLchar* stringsVertexShader =
{
"#version 150 \n"
"in vec3 in_sPosition; \n"
"in vec3 in_sNormal; \n"
"in vec2 in_TextPos; \n"
"uniform mat4 mMVP; \n"
"uniform mat4 mToViewSpace; \n"
"flat out vec3 theNormal; \n"
"out vec3 pointPos; \n"
"out vec2 textCoord; \n"
"void main(void) \n"
"{\n"
" gl_Position = mMVP * vec4(in_sPosition, 1.0); \n"
" textCoord = in_TextPos; \n"
" // Operations in View Space \n"
" vec4 temp4 = mToViewSpace * vec4(in_sPosition, 1.0); \n"
" pointPos = temp4.xyz; \n"
" temp4 = mToViewSpace * vec4(in_sNormal, 0.0); \n"
" theNormal = normalize(temp4.xyz); \n"
"}\n"
};
// Fragment shader for strings (textures) with illumination
const GLchar* stringsFragmentShader =
{
"#version 150 \n"
"uniform vec4 lightProps; // Position in View space, and intensity \n"
"uniform vec3 lightColour; \n"
"uniform sampler2D stringTexture; \n"
"flat in vec3 theNormal; \n"
"in vec3 pointPos; \n"
"in vec2 textCoord; \n"
"out vec4 fragColour; \n"
"// Declare this function \n"
"vec3 Illuminate(in vec4 LiProps, in vec3 LiColour, in vec4 PColour, \n"
" in vec3 PNormal, in vec3 PPos); \n"
"void main(void) \n"
"{\n"
" vec4 colo4 = texture(stringTexture, textCoord); \n"
" vec3 lightRes = Illuminate(lightProps, lightColour, colo4, \n"
" theNormal, pointPos); \n "
" fragColour = vec4(lightRes, colo4.a); \n"
"}\n"
};
// Vertex shader for immutable strings (textures)
const GLchar* stringsImmutableVS =
{
"#version 150 \n"
"in vec3 in_sPosition; \n"
"in vec2 in_TextPos; \n"
"uniform mat4 mMVP; \n"
"out vec2 textCoord; \n"
"void main(void) \n"
"{\n"
" gl_Position = mMVP * vec4(in_sPosition, 1.0); \n"
" textCoord = in_TextPos; \n"
"}\n"
};
// Fragment shader for immutable strings (textures)
const GLchar* stringsImmutableFS =
{
"#version 150 \n"
"uniform sampler2D stringTexture; \n"
"in vec2 textCoord; \n"
"out vec4 fragColour; \n"
"void main(void) \n"
"{\n"
" fragColour= texture(stringTexture, textCoord); \n"
"}\n"
};
// ----------------------------------------------------------------------------
// myOGLShaders
// ----------------------------------------------------------------------------
myOGLShaders::myOGLShaders()
{
m_proId = 0;
m_SHAinitializated = false;
}
myOGLShaders::~myOGLShaders()
{
if ( m_proId )
CleanUp();
}
void myOGLShaders::CleanUp()
{
StopUse();
glDeleteProgram(m_proId);
glFlush();
}
void myOGLShaders::AddCode(const GLchar* shaString, GLenum shaType)
{
// The code is a null-terminated string
shaShas sv = {0, shaType, shaString};
m_shaCode.push_back(sv);
}
void myOGLShaders::AddAttrib(const std::string& name)
{
shaVars sv = {0, name}; //We will set the location later
m_shaAttrib.push_back(sv);
// We don't check the max number of attribute locations (usually 16)
}
void myOGLShaders::AddUnif(const std::string& name)
{
shaVars sv = {0, name};
m_shaUnif.push_back(sv);
}
// Inform GL of the locations in program for the vars for buffers used to feed
// the shader. We use glBindAttribLocation (before linking the gl program) with
// the location we want.
// Since GL 3.3 we could avoid this using in the shader "layout(location=x)...".
// The same names as in the shader must be previously set with AddAttrib()
void myOGLShaders::SetAttribLocations()
{
GLuint loc = 0;
for(shaVars_v::iterator it = m_shaAttrib.begin(); it != m_shaAttrib.end(); ++it)
{
it->loc = loc++;
glBindAttribLocation(m_proId, it->loc, it->name.c_str());
}
}
GLuint myOGLShaders::GetAttribLoc(const std::string& name)
{
for (shaVars_v::iterator it = m_shaAttrib.begin(); it != m_shaAttrib.end(); ++it)
{
if ( it->name == name && it->loc != (GLuint)-1 )
return it->loc;
}
return (GLuint) -1;
}
// Store the locations in program for uniforms vars
bool myOGLShaders::AskUnifLocations()
{
for (shaVars_v::iterator it = m_shaUnif.begin(); it != m_shaUnif.end(); ++it)
{
GLint glret = glGetUniformLocation(m_proId, it->name.c_str());
if ( glret == -1 )
{
// Return now, this GPU program cannot be used because we will
// pass data to unknown/unused uniform locations
return false;
}
it->loc = glret;
}
return true;
}
GLuint myOGLShaders::GetUnifLoc(const std::string& name)
{
for (shaVars_v::iterator it = m_shaUnif.begin(); it != m_shaUnif.end(); ++it)
{
if ( it->name == name && it->loc != (GLuint)-1 )
return it->loc;
}
return (GLuint) -1;
}
// Create a GPU program from the given shaders
void myOGLShaders::Init()
{
MyOnGLError(myoglERR_CLEAR); //clear error stack
bool resC = false;
bool resL = false;
// GLSL code load and compilation
for (shaShas_v::iterator it = m_shaCode.begin(); it != m_shaCode.end(); ++it)
{
it->shaId = glCreateShader(it->typeSha);
glShaderSource(it->shaId, 1, &(it->scode), NULL);
MyOnGLError(myoglERR_SHADERCREATE);
resC = Compile(it->shaId);
if ( !resC )
break;
}
if ( resC )
{
// The program in the GPU
m_proId = glCreateProgram();
for (shaShas_v::iterator it = m_shaCode.begin(); it != m_shaCode.end(); ++it)
{
glAttachShader(m_proId, it->shaId);
}
SetAttribLocations(); //Before linking
resL = LinkProg(m_proId);
}
// We don't need them any more
for (shaShas_v::iterator it = m_shaCode.begin(); it != m_shaCode.end(); ++it)
{
if ( resC && it->shaId )
{
glDetachShader(m_proId, it->shaId);
}
glDeleteShader(it->shaId);
}
if ( !resC || !resL )
return;
// Log that shaders are OK
MyOnGLError(myoglERR_JUSTLOG, "Shaders successfully compiled and linked.");
// After linking, we can get locations for uniforms
m_SHAinitializated = AskUnifLocations();
if ( !m_SHAinitializated )
MyOnGLError(myoglERR_SHADERLOCATION, " Unused or unrecognized uniform.");
}
// Useful while developing: show shader compilation errors
bool myOGLShaders::Compile(GLuint shaId)
{
glCompileShader(shaId);
GLint Param = 0;
glGetShaderiv(shaId, GL_COMPILE_STATUS, &Param);
if ( Param == GL_FALSE )
{
glGetShaderiv(shaId, GL_INFO_LOG_LENGTH, &Param);
if ( Param > 0 )
{
GLchar* InfoLog = new GLchar[Param];
int nChars = 0;
glGetShaderInfoLog(shaId, Param, &nChars, InfoLog);
MyOnGLError(myoglERR_SHADERCOMPILE, InfoLog);
delete [] InfoLog;
}
return false;
}
return true;
}
// Useful while developing: show shader program linkage errors
bool myOGLShaders::LinkProg(GLuint proId)
{
glLinkProgram(proId);
GLint Param = 0;
glGetProgramiv(proId, GL_LINK_STATUS, &Param);
if ( Param == GL_FALSE )
{
glGetProgramiv(proId, GL_INFO_LOG_LENGTH, &Param);
if ( Param > 0 )
{
GLchar* InfoLog = new GLchar[Param];
int nChars = 0;
glGetProgramInfoLog(proId, Param, &nChars, InfoLog);
MyOnGLError(myoglERR_SHADERLINK, InfoLog);
delete [] InfoLog;
}
return false;
}
return true;
}
bool myOGLShaders::Use()
{
if ( !m_SHAinitializated )
return false;
glUseProgram(m_proId);
return true;
}
void myOGLShaders::StopUse()
{
glUseProgram(0);
}
// Disable generic attributes from VAO.
// This should be needed only for some old card, which uses generic into VAO
void myOGLShaders::DisableGenericVAA()
{
for(shaVars_v::iterator it = m_shaAttrib.begin(); it != m_shaAttrib.end(); ++it)
{
glDisableVertexAttribArray(it->loc);
}
}
// ----------------------------------------------------------------------------
// A point light
// ----------------------------------------------------------------------------
void myLight::Set(const myVec3& position, GLfloat intensity,
GLfloat R, GLfloat G, GLfloat B)
{
m_PosAndIntensisty[0] = (GLfloat) position.x;
m_PosAndIntensisty[1] = (GLfloat) position.y;
m_PosAndIntensisty[2] = (GLfloat) position.z;
m_PosAndIntensisty[3] = (GLfloat) intensity;
m_Colour[0] = R;
m_Colour[1] = G;
m_Colour[2] = B;
}
// ----------------------------------------------------------------------------
// myOGLTriangles
// ----------------------------------------------------------------------------
myOGLTriangles::myOGLTriangles()
{
m_triangVAO = m_bufVertId = m_bufColNorId = m_bufIndexId = 0;
m_triangShaders = NULL;
}
myOGLTriangles::~myOGLTriangles()
{
Clear();
}
void myOGLTriangles::Clear()
{
if ( m_triangShaders )
m_triangShaders->DisableGenericVAA();
// Clear graphics card memory
glBindBuffer(GL_ARRAY_BUFFER, 0);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0);
if ( m_bufIndexId )
glDeleteBuffers(1, &m_bufIndexId);
if ( m_bufColNorId )
glDeleteBuffers(1, &m_bufColNorId);
if ( m_bufVertId )
glDeleteBuffers(1, &m_bufVertId);
// Unbind from context
glBindVertexArray(0);
if ( m_triangVAO )
glDeleteVertexArrays(1, &m_triangVAO);
glFlush(); //Tell GL to execute those commands now, but we don't wait for them
m_triangShaders = NULL;
m_triangVAO = m_bufIndexId = m_bufColNorId = m_bufVertId = 0;
}
void myOGLTriangles::SetBuffers(myOGLShaders* theShader,
GLsizei nuPoints, GLsizei nuTriangs,
const GLfloat* vert, const GLfloat* colo,
const GLfloat* norm, const GLushort* indices)
{
MyOnGLError(myoglERR_CLEAR); //clear error stack
// NOTE: have you realized that I fully trust on parameters being != 0 and != NULL?
// Part 1: Buffers - - - - - - - - - - - - - - - - - - -
// Graphics card buffer for vertices.
// Not shared buffer with colours and normals, why not? Just for fun.
glGenBuffers(1, &m_bufVertId);
glBindBuffer(GL_ARRAY_BUFFER, m_bufVertId);
// Populate the buffer with the array "vert"
GLsizeiptr nBytes = nuPoints * 3 * sizeof(GLfloat); //3 components {x,y,z}
glBufferData(GL_ARRAY_BUFFER, nBytes, vert, GL_STATIC_DRAW);
if ( ! MyOnGLError(myoglERR_BUFFER) )
{
// Likely the GPU got out of memory
Clear();
return;
}
// Graphics card buffer for colours and normals.
glGenBuffers(1, &m_bufColNorId);
glBindBuffer(GL_ARRAY_BUFFER, m_bufColNorId);
// Allocate space for both arrays
nBytes = (nuPoints * 4 + nuTriangs * 3) * sizeof(GLfloat);
glBufferData(GL_ARRAY_BUFFER, nBytes, NULL, GL_STATIC_DRAW);
if ( ! MyOnGLError(myoglERR_BUFFER) )
{
// Likely the GPU got out of memory
Clear();
return;
}
// Populate part of the buffer with the array "colo"
nBytes = nuPoints * 4 * sizeof(GLfloat); // rgba components
glBufferSubData(GL_ARRAY_BUFFER, 0, nBytes, colo);
// Add the array "norm" to the buffer
GLsizeiptr bufoffset = nBytes;
nBytes = nuTriangs * 3 * sizeof(GLfloat);
glBufferSubData(GL_ARRAY_BUFFER, bufoffset, nBytes, norm);
// Graphics card buffer for indices.
glGenBuffers(1, &m_bufIndexId);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, m_bufIndexId);
// Populate the buffer with the array "indices"
// We use "triangle strip". An index for each additional vertex.
nBytes = (3 + nuTriangs - 1) * sizeof(GLushort); //Each triangle needs 3 indices
glBufferData(GL_ELEMENT_ARRAY_BUFFER, nBytes, indices, GL_STATIC_DRAW);
if ( ! MyOnGLError(myoglERR_BUFFER) )
{
// Likely the GPU got out of memory
Clear();
return;
}
// Unbind buffers. We will bind them one by one just now, at VAO creation
glBindBuffer(GL_ARRAY_BUFFER, 0);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0);
m_nuTriangs = nuTriangs;
m_triangShaders = theShader;
MyOnGLError(myoglERR_CLEAR); //clear error stack
// Part 2: VAO - - - - - - - - - - - - - - - - - - -
// Vertex Array Object (VAO) that stores the relationship between the
// buffers and the shader input attributes
glGenVertexArrays(1, &m_triangVAO);
glBindVertexArray(m_triangVAO);
// Set the way of reading (blocks of n floats each) from the current bound
// buffer and passing data to the shader (through the index of an attribute).
// Vertices positions
glBindBuffer(GL_ARRAY_BUFFER, m_bufVertId);
GLuint loc = m_triangShaders->GetAttribLoc("in_Position");
glEnableVertexAttribArray(loc);
glVertexAttribPointer(loc, 3, GL_FLOAT, GL_FALSE, 0, (GLvoid *)0);
// Colours
glBindBuffer(GL_ARRAY_BUFFER, m_bufColNorId);
loc = m_triangShaders->GetAttribLoc("in_Colour");
glEnableVertexAttribArray(loc);
glVertexAttribPointer(loc, 4, GL_FLOAT, GL_FALSE, 0, (GLvoid *)0);
// Normals. Their position in buffer starts at bufoffset
loc = m_triangShaders->GetAttribLoc("in_Normal");
glEnableVertexAttribArray(loc);
glVertexAttribPointer(loc, 3, GL_FLOAT, GL_FALSE, 0, (GLvoid *)bufoffset);
// Indices
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, m_bufIndexId);
// Unbind
glBindVertexArray(0);
glBindBuffer(GL_ARRAY_BUFFER, 0);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0);
// Some log
MyOnGLError(myoglERR_JUSTLOG, "Triangles data loaded into GPU.");
}
void myOGLTriangles::Draw(const GLfloat* unifMvp, const GLfloat* unifToVw,
const myLight* theLight)
{
if ( !m_triangVAO )
return;
MyOnGLError(myoglERR_CLEAR); //clear error stack
if ( ! m_triangShaders->Use() )
return;
// Bind the source data for the shader
glBindVertexArray(m_triangVAO);
// Pass matrices to the shader in column-major order
glUniformMatrix4fv(m_triangShaders->GetUnifLoc("mMVP"), 1, GL_FALSE, unifMvp);
glUniformMatrix4fv(m_triangShaders->GetUnifLoc("mToViewSpace"), 1, GL_FALSE, unifToVw);
// Pass the light, in View coordinates in this sample
glUniform4fv(m_triangShaders->GetUnifLoc("lightProps"), 1, theLight->GetFLightPos());
glUniform3fv(m_triangShaders->GetUnifLoc("lightColour"), 1, theLight->GetFLightColour());
// We have a flat shading, and we want the first vertex data as the flat value
glProvokingVertex(GL_FIRST_VERTEX_CONVENTION);
// Indexed drawing the triangles in strip mode, using 6 indices
glDrawElements(GL_TRIANGLE_STRIP, 6, GL_UNSIGNED_SHORT, (GLvoid *)0);
MyOnGLError(myoglERR_DRAWING_TRI);
// Unbind
glBindVertexArray(0);
m_triangShaders->StopUse();
}
// ----------------------------------------------------------------------------
// myOGLString
// ----------------------------------------------------------------------------
myOGLString::myOGLString()
{
m_bufPosId = m_textureId = m_stringVAO = m_textureUnit = 0;
m_stringShaders = NULL;
}
myOGLString::~myOGLString()
{
Clear();
}
void myOGLString::Clear()
{
if ( m_stringShaders )
m_stringShaders->DisableGenericVAA();
// Clear graphics card memory
glBindBuffer(GL_ARRAY_BUFFER, 0);
if ( m_bufPosId )
glDeleteBuffers(1, &m_bufPosId);
// Unbind from context
glBindVertexArray(0);
glDeleteVertexArrays(1, &m_stringVAO);
if ( m_textureUnit && m_textureId )
{
glActiveTexture(GL_TEXTURE0 + m_textureUnit);
glBindTexture(GL_TEXTURE_2D, 0);
glDeleteTextures(1, &m_textureId);
}
glActiveTexture(GL_TEXTURE0);
glFlush(); //Tell GL to execute those commands now, but we don't wait for them
m_bufPosId = m_textureId = m_stringVAO = m_textureUnit = 0;
m_stringShaders = NULL;
}
void myOGLString::SetStringWithVerts(myOGLShaders* theShader,
const unsigned char* tImage, int tWidth, int tHeigh,
const GLfloat* vert, const GLfloat* norm)
{
MyOnGLError(myoglERR_CLEAR); //clear error stack
if ( !tImage )
return;
// Part 1: Buffers - - - - - - - - - - - - - - - - - - -
// Graphics card buffer for vertices, normals, and texture coords
glGenBuffers(1, &m_bufPosId);
glBindBuffer(GL_ARRAY_BUFFER, m_bufPosId);
// (4+4) (vertices + normals) x 3 components + 4 text-vertices x 2 components
GLsizeiptr nBytes = (8 * 3 + 4 * 2) * sizeof(GLfloat);
glBufferData(GL_ARRAY_BUFFER, nBytes, NULL, GL_STATIC_DRAW);
if ( ! MyOnGLError(myoglERR_BUFFER) )
{
// Likely the GPU got out of memory
Clear();
return;
}
// Populate part of the buffer with the array "vert"
nBytes = 12 * sizeof(GLfloat);
glBufferSubData(GL_ARRAY_BUFFER, 0, nBytes, vert);
// Add the array "norm" to the buffer
GLsizeiptr bufoffset = nBytes;
if ( norm )
{
// Just for string on face, not immutable string
glBufferSubData(GL_ARRAY_BUFFER, bufoffset, nBytes, norm);
}
// Add the array of texture coordinates to the buffer.
// Order is set accordingly with the vertices
// See myOGLManager::SetStringOnPyr()
GLfloat texcoords[8] = { 0.0, 1.0, 0.0, 0.0, 1.0, 1.0, 1.0, 0.0 };
bufoffset += nBytes;
nBytes = 8 * sizeof(GLfloat);
glBufferSubData(GL_ARRAY_BUFFER, bufoffset, nBytes, texcoords);
m_stringShaders = theShader;
MyOnGLError(myoglERR_CLEAR); //clear error stack
// Part 2: VAO - - - - - - - - - - - - - - - - - - -
// Vertex Array Object (VAO) that stores the relationship between the
// buffers and the shader input attributes
glGenVertexArrays(1, &m_stringVAO);
glBindVertexArray(m_stringVAO);
// Set the way of reading (blocks of n floats each) from the current bound
// buffer and passing data to the shader (through the index of an attribute).
// Vertices positions
GLuint loc = m_stringShaders->GetAttribLoc("in_sPosition");
glEnableVertexAttribArray(loc);
glVertexAttribPointer(loc, 3, GL_FLOAT, GL_FALSE, 0, (GLvoid *)0);
// Normals. Their position in buffer starts at bufoffset
bufoffset = 12 * sizeof(GLfloat);
if ( norm )
{
// Just for string on face, not immutable string
loc = m_stringShaders->GetAttribLoc("in_sNormal");
glEnableVertexAttribArray(loc);
glVertexAttribPointer(loc, 3, GL_FLOAT, GL_FALSE, 0, (GLvoid *)bufoffset);
}
// Texture coordinates
bufoffset *= 2; //Normals take same amount of space as vertices
loc = m_stringShaders->GetAttribLoc("in_TextPos");
glEnableVertexAttribArray(loc);
glVertexAttribPointer(loc, 2, GL_FLOAT, GL_FALSE, 0, (GLvoid *)bufoffset);
// Part 3: The texture with the string as an image - - - - - - - -
// Create the bind for the texture
// Same unit for both textures (strings) since their characteristics are the same.
m_textureUnit = 1;
glActiveTexture(GL_TEXTURE0 + m_textureUnit);
glGenTextures(1, &m_textureId); //"Name" of the texture object
glBindTexture(GL_TEXTURE_2D, m_textureId);
// Avoid some artifacts
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
// Do this before glTexImage2D because we only have 1 level, no mipmap
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_BASE_LEVEL, 0);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAX_LEVEL, 0);
// For RGBA default alignment (4) is good. In other circumstances, we may
// need glPixelStorei(GL_UNPACK_ALIGNMENT, 1)
// Load texture into card. No mipmap, so 0-level
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA,
(GLsizei)tWidth, (GLsizei)tHeigh, 0,
GL_RGBA, GL_UNSIGNED_BYTE, tImage);
if ( ! MyOnGLError(myoglERR_TEXTIMAGE) )
{
// Likely the GPU got out of memory
Clear();
return;
}
// Unbind
glBindVertexArray(0);
glBindBuffer(GL_ARRAY_BUFFER, 0);
glBindTexture(GL_TEXTURE_2D, 0);
glActiveTexture(GL_TEXTURE0);
// Some log
MyOnGLError(myoglERR_JUSTLOG, "Texture for string loaded into GPU.");
}
void myOGLString::Draw(const GLfloat* unifMvp, const GLfloat* unifToVw,
const myLight* theLight)
{
if ( !m_stringVAO )
return;
MyOnGLError(myoglERR_CLEAR); //clear error stack
if ( ! m_stringShaders->Use() )
return;
// Bind the source data for the shader
glBindVertexArray(m_stringVAO);
// Pass matrices to the shader in column-major order
glUniformMatrix4fv(m_stringShaders->GetUnifLoc("mMVP"), 1, GL_FALSE, unifMvp);
if ( unifToVw && theLight )
{
// Just for string on face, not immutable string
glUniformMatrix4fv(m_stringShaders->GetUnifLoc("mToViewSpace"), 1, GL_FALSE, unifToVw);
// Pass the light, in View coordinates in this sample
glUniform4fv(m_stringShaders->GetUnifLoc("lightProps"), 1, theLight->GetFLightPos());
glUniform3fv(m_stringShaders->GetUnifLoc("lightColour"), 1, theLight->GetFLightColour());
// We have a flat shading, and we want the first vertex normal as the flat value
glProvokingVertex(GL_FIRST_VERTEX_CONVENTION);
}
// Use our texture unit
glActiveTexture(GL_TEXTURE0 + m_textureUnit);
glBindTexture(GL_TEXTURE_2D, m_textureId);
// The fragment shader will read texture values (pixels) from the texture
// currently active
glUniform1i(m_stringShaders->GetUnifLoc("stringTexture"), m_textureUnit);
// Draw the rectangle made up of two triangles
glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
MyOnGLError(myoglERR_DRAWING_STR);
// Unbind
glBindVertexArray(0);
glBindTexture(GL_TEXTURE_2D, 0);
glActiveTexture(GL_TEXTURE0);
m_stringShaders->StopUse();
}
// ----------------------------------------------------------------------------
// myOGLImmutString
// ----------------------------------------------------------------------------
void myOGLImmutString::SetImmutString(myOGLShaders* theShader,
const unsigned char* tImage, int tWidth, int tHeigh)
{
// Make a rectangle of the same size as the image. Order of vertices matters.
// Set a 2 pixels margin
double imaVerts[12];
imaVerts[0] = 2.0 ; imaVerts[1] = 2.0 ; imaVerts[2] = -1.0;
imaVerts[3] = 2.0 ; imaVerts[4] = 2.0 + tHeigh; imaVerts[5] = -1.0;
imaVerts[6] = 2.0 + tWidth; imaVerts[7] = 2.0 ; imaVerts[8] = -1.0;
imaVerts[9] = 2.0 + tWidth; imaVerts[10] = 2.0 + tHeigh; imaVerts[11] = -1.0;
// GLFloat version
GLfloat fimaVerts[12];
SetAsGLFloat4x4(imaVerts, fimaVerts, 12);
// Call the base class without normals, it will handle this case
SetStringWithVerts(theShader, tImage, tWidth, tHeigh, fimaVerts, NULL);
}
void myOGLImmutString::SetOrtho(int winWidth, int winHeight)
{
// We want an image always of the same size, regardless of window size.
// The orthogonal projection with the whole window achieves it.
MyOrtho(0.0, winWidth, 0.0, winHeight, -1.0, 1.0, m_dOrtho);
// Store the 'float' matrix
SetAsGLFloat4x4(m_dOrtho, m_fOrtho, 16);
}
// ----------------------------------------------------------------------------
// myOGLCamera
// ----------------------------------------------------------------------------
myOGLCamera::myOGLCamera()
{
m_needMVPUpdate = true; //Matrix must be updated
InitPositions();
}
void myOGLCamera::InitPositions()
{
// We have a tetrahedron centered at origin and edge length = 200
m_centerOfWorld.x = m_centerOfWorld.y = m_centerOfWorld.z = 0.0;
// The radius of the bounding sphere
m_radiusOfWorld = 122.4745;
// From degrees to radians
double degToRad = (double) 4.0 * atan(1.0) / 180.0;
// Angle of the field of view
m_fov = 40.0 * degToRad; //radians
// Position the camera far enough so we can see the whole world.
// The camera is between X and Z axis, below the pyramid
double tmpv = m_radiusOfWorld / sin(m_fov/2.0);
tmpv *= 1.05; // 5% margin
m_camPosition.x = m_centerOfWorld.x + tmpv * cos(75.0 * degToRad);
m_camPosition.z = m_centerOfWorld.z + tmpv * sin(75.0 * degToRad);
m_camPosition.y = m_centerOfWorld.y - m_radiusOfWorld;
// This camera looks always at center
m_camTarget = m_centerOfWorld;
// A vector perpendicular to Position-Target heading Y+
myVec3 vper = MyNormalize(m_camTarget - m_camPosition);
m_camUp = myVec3(0.0, 1.0, 0.0);
m_camUp = MyCross(m_camUp, vper);
m_camUp = MyNormalize( MyCross(vper, m_camUp) );
tmpv = MyDistance(m_camPosition, m_centerOfWorld);
// Calculate distances, not coordinates, with some margins
// Near clip-plane distance to the camera
m_nearD = tmpv - 1.10 * m_radiusOfWorld - 5.0;
// Far clip-plane distance to the camera
m_farD = tmpv + 1.10 * m_radiusOfWorld + 5.0;
// The "View" matrix. We will not change it any more in this sample
MyLookAt(m_camPosition, m_camUp, m_camTarget, m_dView);
// The initial "Model" matrix is the Identity matrix
MyRotate(myVec3(0.0, 0.0, 1.0), 0.0, m_dMode);
// Nothing else. "View" matrix is calculated at ViewSizeChanged()
}
void myOGLCamera::ViewSizeChanged(int newWidth, int newHeight)
{
// These values are also used for MouseRotation()
m_winWidth = newWidth;
m_winHeight = newHeight;
// Calculate the projection matrix
double aspect = (double) newWidth / newHeight;
MyPerspective(m_fov, aspect, m_nearD, m_farD, m_dProj);
// Inform we need to calculate MVP matrix
m_needMVPUpdate = true;
}
const GLfloat* myOGLCamera::GetFloatMVP()
{
UpdateMatrices();
return m_fMVP;
}
const GLfloat* myOGLCamera::GetFloatToVw()
{
UpdateMatrices();
return m_fToVw;
}
void myOGLCamera::UpdateMatrices()
{
if ( m_needMVPUpdate )
{
MyMatMul4x4(m_dView, m_dMode, m_dToVw);
MyMatMul4x4(m_dProj, m_dToVw, m_dMVP);
// Store the 'float' matrices
SetAsGLFloat4x4(m_dToVw, m_fToVw, 16);
SetAsGLFloat4x4(m_dMVP, m_fMVP, 16);
m_needMVPUpdate = false;
}
}
void myOGLCamera::MouseRotation(int fromX, int fromY, int toX, int toY)
{
if ( fromX == toX && fromY == toY )
return; //no rotation
// 1. Obtain axis of rotation and angle simulating a virtual trackball "r"
// 1.1. Calculate normalized coordinates (2x2x2 box).
// The trackball is a part of sphere of radius "r" (the rest is hyperbolic)
// Use r= 0.8 for better maximum rotation (more-less 150 degrees)
double xw1 = (2.0 * fromX - m_winWidth) / m_winWidth;
double yw1 = (2.0 * fromY - m_winHeight) / m_winHeight;
double xw2 = (2.0 * toX - m_winWidth) / m_winWidth;
double yw2 = (2.0 * toY - m_winHeight) / m_winHeight;
double z1 = GetTrackballZ(xw1, yw1, 0.8);
double z2 = GetTrackballZ(xw2, yw2, 0.8);
// 1.2. With normalized vectors, compute axis from 'cross' and angle from 'dot'
myVec3 v1(xw1, yw1, z1);
myVec3 v2(xw2, yw2, z2);
v1 = MyNormalize(v1);
v2 = MyNormalize(v2);
myVec3 axis(MyCross(v1, v2));
// 'axis' is in camera coordinates. Transform it to world coordinates.
double mtmp[16];
MyMatInverse(m_dView, mtmp);
myVec4 res = MyMatMul4x1(mtmp, myVec4(axis));
axis.x = res.x;
axis.y = res.y;
axis.z = res.z;
axis = MyNormalize(axis);
double angle = AngleBetween(v1, v2);
// 2. Compute the model transformation (rotate the model) matrix
MyRotate(axis, angle, mtmp);
// Update "Model" matrix
double mnew[16];
MyMatMul4x4(mtmp, m_dMode, mnew);
for (size_t i = 0; i<16; ++i)
m_dMode[i] = mnew[i];
// Inform we need to calculate MVP matrix
m_needMVPUpdate = true;
}
// Return the orthogonal projection of (x,y) into a sphere centered on the screen
// and radius 'r'. This makes some (x,y) to be outside of circle r='r'. We avoid
// this issue by using a hyperbolic sheet for (x,y) outside of r = 0.707 * 'r'.
double myOGLCamera::GetTrackballZ(double x, double y, double r)
{
double d = x*x + y*y;
double r2 = r*r;
return (d < r2/2.0) ? sqrt(r2 - d) : r2/2.0/sqrt(d);
}
// ----------------------------------------------------------------------------
// myOGLManager
// ----------------------------------------------------------------------------
myOGLManager::myOGLManager(myOGLErrHandler* extErrHnd)
{
externalMyOGLErrHandler = extErrHnd;
MyOnGLError(myoglERR_CLEAR); //clear error stack
}
myOGLManager::~myOGLManager()
{
MyOnGLError(myoglERR_CLEAR); //clear error stack
// Force GPU finishing before the context is deleted
glFinish();
}
/* Static */
bool myOGLManager::Init()
{
// Retrieve the pointers to OGL functions we use in this sample
return MyInitGLPointers();
}
const GLubyte* myOGLManager::GetGLVersion()
{
return glGetString(GL_VERSION);
}
const GLubyte* myOGLManager::GetGLVendor()
{
return glGetString(GL_VENDOR);
}
const GLubyte* myOGLManager::GetGLRenderer()
{
return glGetString(GL_RENDERER);
}
void myOGLManager::SetShadersAndTriangles()
{
// The shaders attributes and uniforms
m_TriangShaders.AddAttrib("in_Position");
m_TriangShaders.AddAttrib("in_Colour");
m_TriangShaders.AddAttrib("in_Normal");
m_TriangShaders.AddUnif("mMVP");
m_TriangShaders.AddUnif("mToViewSpace");
m_TriangShaders.AddUnif("lightProps");
m_TriangShaders.AddUnif("lightColour");
m_TriangShaders.AddCode(triangVertexShader, GL_VERTEX_SHADER);
m_TriangShaders.AddCode(illuminationShader, GL_FRAGMENT_SHADER);
m_TriangShaders.AddCode(triangFragmentShader, GL_FRAGMENT_SHADER);
m_TriangShaders.Init();
m_StringShaders.AddAttrib("in_sPosition");
m_StringShaders.AddAttrib("in_sNormal");
m_StringShaders.AddAttrib("in_TextPos");
m_StringShaders.AddUnif("mMVP");
m_StringShaders.AddUnif("mToViewSpace");
m_StringShaders.AddUnif("lightProps");
m_StringShaders.AddUnif("lightColour");
m_StringShaders.AddUnif("stringTexture");
m_StringShaders.AddCode(stringsVertexShader, GL_VERTEX_SHADER);
m_StringShaders.AddCode(illuminationShader, GL_FRAGMENT_SHADER);
m_StringShaders.AddCode(stringsFragmentShader, GL_FRAGMENT_SHADER);
m_StringShaders.Init();
m_ImmutStringSha.AddAttrib("in_sPosition");
m_ImmutStringSha.AddAttrib("in_TextPos");
m_ImmutStringSha.AddUnif("mMVP");
m_ImmutStringSha.AddUnif("stringTexture");
m_ImmutStringSha.AddCode(stringsImmutableVS, GL_VERTEX_SHADER);
m_ImmutStringSha.AddCode(stringsImmutableFS, GL_FRAGMENT_SHADER);
m_ImmutStringSha.Init();
// The point light. Set its color as full white.
// In this sample we set the light position same as the camera position
// In View space, camera position is {0, 0, 0}
m_Light.Set(myVec3(0.0, 0.0, 0.0), 1.0, 1.0, 1.0, 1.0);
// The triangles data
m_Triangles.SetBuffers(&m_TriangShaders, 4, 4, gVerts, gColours, gNormals, gIndices);
}
void myOGLManager::SetStringOnPyr(const unsigned char* strImage, int iWidth, int iHeigh)
{
// Some geometry. We want a rectangle close to face 0-1-2 (X-Z plane).
// The rectangle must preserve strImage proportions. If the height of the
// rectangle is "h" and we want to locate it with its largest side parallel
// to the edge of the face and at distance= h/2, then the rectangle width is
// rw = edgeLength - 2 * ((h/2 + h + h/2)/tan60) = edgeLength - 4*h/sqrt(3)
// If h/rw = Prop then
// rw = edgeLength / (1+4/sqrt(3)*Prop) and h = Prop * rw
double edgeLen = MyDistance(myVec3(gVerts[0], gVerts[1], gVerts[2]),
myVec3(gVerts[6], gVerts[7], gVerts[8]));
GLfloat prop = ((GLfloat) iHeigh) / ((GLfloat) iWidth);
GLfloat rw = float(edgeLen) / (1 + 4 * prop / std::sqrt(3.0f));
GLfloat h = prop * rw;
GLfloat de = 2 * h / std::sqrt(3.0f);
// A bit of separation of the face so as to avoid z-fighting
GLfloat rY = gVerts[1] - 0.01f; // Towards outside
GLfloat sVerts[12];
// The image was created top to bottom, but OpenGL axis are bottom to top.
// The image would display upside down. We avoid it choosing the right
// order of vertices and texture coords. See myOGLString::SetStringWithVerts()
sVerts[0] = gVerts[6] + de; sVerts[1] = rY; sVerts[2] = gVerts[8] + h / 2;
sVerts[3] = sVerts[0] ; sVerts[4] = rY; sVerts[5] = sVerts[2] + h;
sVerts[6] = sVerts[0] + rw; sVerts[7] = rY; sVerts[8] = sVerts[2];
sVerts[9] = sVerts[6] ; sVerts[10] = rY; sVerts[11] = sVerts[5];
// Normals for the rectangle illumination, same for the four vertices
const GLfloat strNorms[] = { gNormals[0], gNormals[1], gNormals[2],
gNormals[0], gNormals[1], gNormals[2],
gNormals[0], gNormals[1], gNormals[2],
gNormals[0], gNormals[1], gNormals[2]};
// The texture data for the string on the face of the pyramid
m_StringOnPyr.SetStringWithVerts(&m_StringShaders, strImage, iWidth, iHeigh,
sVerts, strNorms);
}
void myOGLManager::SetImmutableString(const unsigned char* strImage,
int iWidth, int iHeigh)
{
m_ImmString.SetImmutString(&m_ImmutStringSha, strImage, iWidth, iHeigh);
}
void myOGLManager::SetViewport(int x, int y, int width, int height)
{
if (width < 1) width = 1;
if (height < 1) height = 1;
glViewport(x, y, (GLsizei)width, (GLsizei)height);
// The camera handles perspective projection
m_Camera.ViewSizeChanged(width, height);
// And this object handles its own orthogonal projection
m_ImmString.SetOrtho(width, height);
}
void myOGLManager::Render()
{
glEnable(GL_DEPTH_TEST);
glDepthFunc(GL_LEQUAL);
glEnable(GL_BLEND);
glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
glClearColor((GLfloat)0.15, (GLfloat)0.15, 0.0, (GLfloat)1.0); // Dark, but not black.
glClear( GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT );
m_Triangles.Draw(m_Camera.GetFloatMVP(), m_Camera.GetFloatToVw(), &m_Light);
m_StringOnPyr.Draw(m_Camera.GetFloatMVP(), m_Camera.GetFloatToVw(), &m_Light);
// This string is at the very front, whatever z-coords are given
glDisable(GL_DEPTH_TEST);
m_ImmString.Draw(m_ImmString.GetFloatMVP(), NULL, NULL);
}
void myOGLManager::OnMouseButDown(int posX, int posY)
{
// Just save mouse position
m_mousePrevX = posX;
m_mousePrevY = posY;
}
void myOGLManager::OnMouseRotDragging(int posX, int posY)
{
m_Camera.MouseRotation(m_mousePrevX, m_mousePrevY, posX, posY);
m_mousePrevX = posX;
m_mousePrevY = posY;
}