Triangle for GLSL color conversion (C language)

 #include 
 
  #include 
  
   #include 
   
    #include readtext.h#ifdef _APPLE_#include 
    
     #else#define FREEGLUT_STATIC#include 
     
      #endif#pragma  comment(lib, readtext.lib)GLuint vShader, fShader, programHandle;GLint  vaoHandle, vboHandles[2], positionBufferHandle, colorBufferHandle;GLuint elapseTimeUniformLocation, loopDurationLocation, fragLoopDurationLocation;GLint positionLocation, colorLocation;////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////int infoLogLength =0;int charWritten =0;char *infoLog;///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////float positionData[]={  0.8f, 0.0f, 0.0f,                        -0.8f, 0.0f, 0.0f,     0.0f, 0.8f, 0.0f};////////////////////////////////////////////float colorData[]= { 1.0, 0.0, 0.0,//                     0.0, 1.0, 0.0,//   0.0, 0.0, 1.0};//////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////void SetupShader(){char *renderer;char *vender;char *version;char *glslVersion;////////////////////////////////////char *vs, *fs;char *vv, *ff;char *txt;/////////////////////////////////////////////////////////////renderer =glGetString(GL_RENDERER);vender =glGetString(GL_VENDOR);version =glGetString(GL_VERSION);glslVersion =glGetString(GL_SHADING_LANGUAGE_VERSION);printf(graphic card:%s , renderer);printf(graphic company:%s , vender);printf(openGL version:%s , version);printf(GLSL version: %s , glslVersion);printf(*****************************************************);//////////////////////////////////////////////////////////////    //txt =readText(2.txt);//printf(%s,txt);//putchar(10);vShader =glCreateShader(GL_VERTEX_SHADER);vs =readText(shader/triangle.vert);//printf(%s,vs);vv =vs;if(vShader ==0){printf(Error: fail to create shader!);exit(1);}glShaderSource(vShader, 1, &vv, NULL);glCompileShader(vShader);free(vs);glGetShaderiv(vShader, GL_INFO_LOG_LENGTH, &infoLogLength);if(infoLogLength >0){infoLog =(char *)malloc(infoLogLength);glGetShaderInfoLog(vShader, infoLogLength, &charWritten, infoLog);printf(%s, infoLog);printf(**********************************************************);free(infoLog);}/////////////////////////////////////////////////////////////////////////////////fShader =glCreateShader(GL_FRAGMENT_SHADER);if(fShader ==0){printf(can't create fragment shader! );exit(1);}    fs =readText(shader/triangle.frag);    //printf(%s ,fs);ff= fs;glShaderSource(fShader, 1, &ff, NULL);glCompileShader(fShader);free(fs);glGetShaderiv(fShader, GL_INFO_LOG_LENGTH, &infoLogLength);if(infoLogLength >0){infoLog =(char *)malloc(infoLogLength);glGetShaderInfoLog(fShader, infoLogLength, &charWritten, infoLog);////////charWritten is printf(%s ,infoLog);printf(***********************************************************);free(infoLog);}//////////////////////////////////////////////////////////////////////////programHandle =glCreateProgram();glAttachShader(programHandle, vShader);glAttachShader(programHandle, fShader);glLinkProgram(programHandle);glGetProgramiv(programHandle, GL_INFO_LOG_LENGTH, &infoLogLength);if(infoLogLength >0){infoLog =(char *)malloc(infoLogLength);glGetProgramInfoLog(programHandle, infoLogLength, &charWritten, infoLog);printf(%s , infoLog);printf(**************************************************************************);free(infoLog);}glUseProgram(programHandle);}//////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////void InitVBO(){glGenBuffers(2, vboHandles);positionBufferHandle =vboHandles[0];//colorBufferHandle =vboHandles[1];    //////////////////////////////////////glBindBuffer(GL_ARRAY_BUFFER, positionBufferHandle);glBufferData(GL_ARRAY_BUFFER, sizeof(positionData), positionData,GL_STATIC_DRAW);//glBindBuffer(GL_ARRAY_BUFFER, colorBufferHandle);//glBufferData(GL_ARRAY_BUFFER, sizeof(colorData), colorData, GL_STATIC_DRAW);//////////////////////////////////////////    glGenVertexArrays(1, &vaoHandle);glBindVertexArray(vaoHandle);/////////////////////////////////////////////glEnableVertexAttribArray(0);//glEnableVertexAttribArray(1);///////////////////////////////////glBindBuffer(GL_ARRAY_BUFFER, positionBufferHandle);glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 0, NULL);//glBindBuffer(GL_ARRAY_BUFFER, colorBufferHandle);//glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, 0, NULL);}///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////void SetupRC(){glewInit();SetupShader();InitVBO();glClearColor(1.0, 0.0, 0.0, 1.0);}////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////void RenderScene(){glClear(GL_COLOR_BUFFER_BIT );glBindVertexArray(vaoHandle);glDrawArrays(GL_TRIANGLES, 0, 3);glBindVertexArray(0);elapseTimeUniformLocation =glGetUniformLocation(programHandle, time);fragLoopDurationLocation =glGetUniformLocation(programHandle,fragLoopDuration);    loopDurationLocation =glGetUniformLocation(programHandle, loopDuration);//printf(%d%d,elapseTimeUniformLocation, loopDurationLocation);glUniform1f(loopDurationLocation, 5.0f);glUniform1f(fragLoopDurationLocation, 10.0f);glUniform1f(elapseTimeUniformLocation, glutGet(GLUT_ELAPSED_TIME)/1000.0f );glutSwapBuffers();glutPostRedisplay();}///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////int main(int argc, char *argv[]){glutInit(&argc, argv);glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGBA);glutInitWindowSize(800, 600);glutInitWindowPosition(0,0);glutCreateWindow(second triangle:active!);SetupRC();glutDisplayFunc(RenderScene);glutMainLoop();return 0;}
     
    
   
  
 

Triangle. vert

 

#version 400layout(location =0) in vec3 vertexPosition;uniform float loopDuration;uniform float time;void main(){float timeScale = 3.14159f * 2.0f / loopDuration;float currTime = mod(time, loopDuration);vec4 totalOffset = vec4(cos(currTime * timeScale) * 0.5f,sin(currTime * timeScale) * 0.5f, 0.0f,0.0f);gl_Position = vec4(vertexPosition,1.0) + totalOffset;}

Triangle. frag

 

 

#version 400out vec4 fragColor;uniform float fragLoopDuration;uniform float time;const vec4 firstColor =vec4(1.0f, 0.0f, 0.0f, 1.0f);const vec4 secondColor =vec4(0.0f, 1.0f, 0.0f, 1.0f);void main(){float currentTime =mod(time, fragLoopDuration);float currentLerp =currentTime/fragLoopDuration;fragColor =mix(firstColor, secondColor, currentLerp); }