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OpenGLRenderer.mm

/*

     File: OpenGLRenderer.mm

 Abstract: The renderer class creates and draws the OpenGL shaders. This is where we demonstrate how to do conditional rendering based on an occlusion query.

  Version: 1.1

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*/

#import "OpenGLRenderer.h"

#import "TriToothedGearFlatModel.h"

#include <stdlib.h>

#include <stdio.h>

#include <string.h>

#include <assert.h>

#define glError() { \

GLenum err = glGetError(); \

while (err != GL_NO_ERROR) { \

__builtin_printf("glError: %s caught at %s:%u\n", (char *)gluErrorString(err), __FILE__, __LINE__); \

err = glGetError(); \

exit(-1); \

} \

typedef struct {

    const char *vert, *frag;

} programInfo_t;

programInfo_t programFileName[kProgramCount] = {

    { "ConditionalRender.vs",   "ConditionalRender.fs"     },

    { "color.vs",              "color.fs"     },

};

GLboolean loadShader(GLenum shaderType, const GLchar** shaderText, GLint* shaderID);

GLboolean linkShaders(GLint* program, GLint vertShaderID, GLint fragShaderID);

@implementation OpenGLRenderer

#pragma mark General Setup

- (id)init

    if (self = [super init])

        animationDelta = 1.5;

        animationStep = 0.0;

        kAnimationLoopValue = 360.0 / animationDelta;

        animate = YES;

        xAxisAngle = 0.0;

        zAxisAngle = 0.0;

    return self;

- (void)dealloc

    glFinish();

    glBindVertexArray(0);

    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0);

    glBindBuffer(GL_ARRAY_BUFFER, 0);

    glDeleteBuffers(4, &triToothedGearFlat->vertsID);

    free(triToothedGearFlat);

    glDeleteBuffers(1, &quadID);

    glDeleteBuffers(1, &quadElementID);

    glDeleteVertexArrays(1, &gearVAOId);

    glDeleteVertexArrays(1, &quadVAOId);

    glUseProgram(0);

    int i = 0;

    for (; i < kProgramCount; i++) {

        glDeleteProgram(programs[i]);

    for (; i < kShaderCount; i++) {

        glDeleteShader(shaders[i]);

    [super dealloc];

- (BOOL)setupScene

    lightPos.x = 0.0; lightPos.y = 5.0; lightPos.z = 0.0; lightPos.w = 1.0;

    lightColor.x = 0.15; lightColor.y = 0.15; lightColor.z = 0.15;

    GLfloat quad[] =

        //     x    y    z    s    t

        -1.0,-1.0, 1.0, 0.0, 0.0,

        1.0,-1.0, 1.0, 1.0, 0.0,

        1.0, 1.0, 1.0, 1.0, 1.0,

        -1.0, 1.0, 1.0, 0.0, 1.0,

};

    GLushort indexes[] =

        0,1,3,2,

};

    // gear model

    glGenVertexArrays(1, &gearVAOId);

    glBindVertexArray(gearVAOId);

    triToothedGearFlat = (quadric*) malloc(sizeof(quadric));

    triToothedGearFlat->vertCount = GEAR_VERTEX_COUNT;

    triToothedGearFlat->indexCount = GEAR_INDEX_COUNT;

    glGenBuffers(4, &triToothedGearFlat->vertsID);

    glBindBuffer(GL_ARRAY_BUFFER, triToothedGearFlat->vertsID);

    glBufferData(GL_ARRAY_BUFFER, triToothedGearFlat->vertCount*3*sizeof(GLfloat), vertices, GL_STATIC_DRAW);

    glBindBuffer(GL_ARRAY_BUFFER, triToothedGearFlat->colorsID);

    glBufferData(GL_ARRAY_BUFFER, triToothedGearFlat->vertCount*3*sizeof(GLfloat), colors, GL_STATIC_DRAW);

    glBindBuffer(GL_ARRAY_BUFFER, triToothedGearFlat->normalsID);

    glBufferData(GL_ARRAY_BUFFER, triToothedGearFlat->vertCount*3*sizeof(GLfloat), normals, GL_STATIC_DRAW);

    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, triToothedGearFlat->indicesID);

    glBufferData(GL_ELEMENT_ARRAY_BUFFER, triToothedGearFlat->indexCount*sizeof(GLuint), indices, GL_STATIC_DRAW);

    // quad

    glGenVertexArrays(1, &quadVAOId);

    glBindVertexArray(quadVAOId);

    glGenBuffers(1, &quadID);

    glGenBuffers(1, &quadElementID);

    glBindBuffer(GL_ARRAY_BUFFER, quadID);

    glBufferData(GL_ARRAY_BUFFER, sizeof(quad), &quad[0], GL_STATIC_DRAW);

    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, quadElementID);

    glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(indexes), &indexes[0], GL_STATIC_DRAW);

    return YES;

- (BOOL)setupGL

    if(![self setupScene])

        return NO;

    if([self loadShaders])

        return NO;

    //set up a default camera matrix

    [self regenCameraMatrix];

    glEnable(GL_DEPTH_TEST);

    glEnable(GL_CULL_FACE);

    glViewport(0, 0, width, height);

    glGenQueries(1, &query);

    //the gear's normals use that of the first vertex

    glProvokingVertexEXT(GL_FIRST_VERTEX_CONVENTION_EXT);

    return YES;

- (void)reshapeToWidth:(GLsizei)w height:(GLsizei)h

    width = w;

    height = h;

    glViewport(0, 0, width, height);

#pragma mark Rendering

- (void)draw

    if(animate)

        animationStep = (animationStep+1) % kAnimationLoopValue;

    glClearColor(0.0,0.0,0.0,0.0);

/*

     if you can guarantee you'll touch every pixel, you don't need to clear

     the color buffer. However, this demo can't guarantee that!

*/

    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

    glEnable(GL_DEPTH_TEST);

    glBindVertexArray(gearVAOId);

    glUseProgram(programs[0]);

    GLKMatrix4 projectionMatrix = GLKMatrix4MakePerspective(75.0 * (M_PI/180.0), ((GLdouble) width) / ((GLdouble) height), 0.1, 100.0);

    glUniformMatrix4fv(projectionMatrixLocation, 1, GL_FALSE, (const GLfloat*) &projectionMatrix);

    GLKVector4 lightPosition = GLKMatrix4MultiplyVector4(cameraMatrix, lightPos);

    GLKMatrix4 rotMatrix = GLKMatrix4MakeRotation(animationStep*animationDelta * (M_PI/180.0), 1.0, 0.0, 1.0);

    glUniformMatrix4fv(cameraMatrixLocation, 1, GL_FALSE, (const GLfloat*) &cameraMatrix);

    glUniform3fv(lightPosLocation, 1, (const GLfloat*) &lightPosition);

    glUniform3fv(lightColorLocation, 1, (const GLfloat*) &lightColor);

    glBindBuffer(GL_ARRAY_BUFFER, triToothedGearFlat->vertsID);

    glVertexAttribPointer(attribPosition, 3, GL_FLOAT, GL_FALSE, 0, NULL);

    glEnableVertexAttribArray(attribPosition);

    glBindBuffer(GL_ARRAY_BUFFER, triToothedGearFlat->normalsID);

    glVertexAttribPointer(attribNormal, 3, GL_FLOAT, GL_FALSE, 0, NULL);

    glEnableVertexAttribArray(attribNormal);

    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, triToothedGearFlat->indicesID);

    int cols = 7, rows = 4, slices = 20;

    float initialx = 1.25*-(cols / 2.0);

    float initialy = -(rows / 2.0);

    int i,j,k;

    //seeding every frame so the colors don't jump around

    srand(0);

    for (k = 0; k < slices/3.0; k++) {

        GLKVector4 color = {(rand()%255) / 255.0, (rand()%255) / 255.0, (rand()%255) / 255.0, 1.0};

        glUniform4fv(colorLocation, 1, (const GLfloat*) &color);

        for (i=0; i < cols; i++) {

            for (j = 0; j < rows; j++) {

                GLKMatrix4 tm, f;

                tm = GLKMatrix4MakeTranslation(initialx+i*1.5, initialy+(j), -k*1.5);

                f = GLKMatrix4Multiply(tm, rotMatrix);

                glUniformMatrix4fv(modelTransformMatrixLocation, 1, GL_FALSE, (const GLfloat*) &f);

                glUniform1f(scaleLocation, 0.25);

                glDrawElements(GL_TRIANGLES, triToothedGearFlat->indexCount, GL_UNSIGNED_INT, NULL);

    //draw the covering plane

    glBindVertexArray(quadVAOId);

    glUseProgram(programs[1]);

    GLKMatrix4 scaleMatrix = GLKMatrix4MakeScale(9.0, 7.0, -9.0);

    GLKMatrix4 MVPMatrix = GLKMatrix4Multiply(projectionMatrix, scaleMatrix);

    glUniformMatrix4fv(MVPLocation, 1, GL_FALSE, (const GLfloat*) &MVPMatrix);

    glUniform4f(constantColorLocation, 1.0, 1.0, 1.0, 1.0);

    glBindBuffer(GL_ARRAY_BUFFER, quadID);

    glVertexAttribPointer(inVertexLocation, 3, GL_FLOAT, GL_FALSE, sizeof(GLfloat)*5, NULL);

    glEnableVertexAttribArray(inVertexLocation);

    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, quadElementID);

    glDrawElements(GL_TRIANGLE_STRIP, 4, GL_UNSIGNED_SHORT, NULL);

/*

     This should be a bounding volume on the conditionally rendered objects.

     We don't actually want to draw the volume, so we turn writes off.

*/

    glColorMask(GL_FALSE, GL_FALSE, GL_FALSE, GL_FALSE);

    glDepthMask(GL_FALSE);

    glBeginQuery(GL_SAMPLES_PASSED_ARB, query);

    scaleMatrix = GLKMatrix4MakeScale(8.0, 6.0, -11.0);

    MVPMatrix = GLKMatrix4Multiply(projectionMatrix, scaleMatrix);

    glUniformMatrix4fv(MVPLocation, 1, GL_FALSE, (const GLfloat*) &MVPMatrix);

    glDrawElements(GL_TRIANGLE_STRIP, 4, GL_UNSIGNED_SHORT, NULL);

    glEndQuery(GL_SAMPLES_PASSED_ARB);

    glColorMask(GL_TRUE, GL_TRUE, GL_TRUE, GL_TRUE);

    glDepthMask(GL_TRUE);

    //reset state

    glBindVertexArray(gearVAOId);

    glBindBuffer(GL_ARRAY_BUFFER, triToothedGearFlat->vertsID);

    glVertexAttribPointer(attribPosition, 3, GL_FLOAT, GL_FALSE, 0, NULL);

    glBindBuffer(GL_ARRAY_BUFFER, triToothedGearFlat->normalsID);

    glVertexAttribPointer(attribNormal, 3, GL_FLOAT, GL_FALSE, 0, NULL);

    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, triToothedGearFlat->indicesID);

    //do the conditional render

    glUseProgram(programs[0]);

    glBeginConditionalRenderNV(query, GL_QUERY_WAIT_NV);

    for (; k < slices; k++) {

        GLKVector4 color = {(rand()%255) / 255.0, (rand()%255) / 255.0, (rand()%255) / 255.0, 1.0};

        glUniform4fv(colorLocation, 1, (const GLfloat*) &color);

        for (i=0; i < cols; i++) {

            for (j = 0; j < rows; j++) {

                GLKMatrix4 tm, f;

                tm = GLKMatrix4MakeTranslation(initialx+i*1.5, initialy+(j), -k*1.5);

                f = GLKMatrix4Multiply(tm, rotMatrix);

                glUniformMatrix4fv(modelTransformMatrixLocation, 1, GL_FALSE, (const GLfloat*) &f);

                glUniform1f(scaleLocation, 0.25);

                glDrawElements(GL_TRIANGLES, triToothedGearFlat->indexCount, GL_UNSIGNED_INT, NULL);

    glEndConditionalRenderNV();

- (void)toggleAnimation

    animate = !animate;

#pragma mark Camera Utility

- (void)regenCameraMatrix

    // set up a default camera matrix

    GLKMatrix4 modelView = GLKMatrix4MakeTranslation(0, 0, -6.0);

    modelView = GLKMatrix4Rotate(modelView, xAxisAngle, 1, 0, 0);

    cameraMatrix = GLKMatrix4Rotate(modelView, zAxisAngle, 0, 0, 1);

- (void)applyCameraMovementWdx:(float)dx dy:(float)dy

    xAxisAngle += dy/3 * (M_PI/180.0);

    zAxisAngle += dx/3 * (M_PI/180.0);

    [self regenCameraMatrix];

#pragma mark Shader Loading

- (GLshort)loadShaders

    for (int i=0; i < kProgramCount; i++)

        // vertex shader

        GLchar* shader = [self loadShaderFromFile:programFileName[i].vert];

        if (!shader) {

            return 1;

        if(!loadShader(GL_VERTEX_SHADER, (const GLchar**) &shader, &shaders[i*2])) {

            return 1;

        free(shader);

        // fragment shader

        shader = [self loadShaderFromFile:programFileName[i].frag];

        if (!shader) {

            return 2;

        if(!loadShader(GL_FRAGMENT_SHADER, (const GLchar**) &shader, &shaders[i*2+1])) {

            return 2;

        free(shader);

        if(!linkShaders(&programs[i], shaders[i*2], shaders[i*2+1]))

            return 3;

    scaleLocation = glGetUniformLocation(programs[0], "scale");

    cameraMatrixLocation = glGetUniformLocation(programs[0], "cameraMatrix");

    modelTransformMatrixLocation = glGetUniformLocation(programs[0], "modelTransformMatrix");

    projectionMatrixLocation = glGetUniformLocation(programs[0], "projectionMatrix");

    colorLocation = glGetUniformLocation(programs[0], "color");

    lightPosLocation = glGetUniformLocation(programs[0], "lightPos");

    lightColorLocation = glGetUniformLocation(programs[0], "lightColor");

    attribNormal = glGetAttribLocation(programs[0], "attribNormal");

    attribPosition = glGetAttribLocation(programs[0], "attribPosition");

    MVPLocation = glGetUniformLocation(programs[1], "MVP");

    constantColorLocation = glGetUniformLocation(programs[1], "constantColor");

    inVertexLocation = glGetAttribLocation(programs[1], "inVertex");

    glError();

    return 0;

- (GLchar*)loadShaderFromFile:(const char*)shaderName

    const char* resourcePath = [[[NSBundle mainBundle] resourcePath] cStringUsingEncoding:NSASCIIStringEncoding];

    char pathToShader[255];

    sprintf(&pathToShader[0], "%s/%s", resourcePath, shaderName);

    FILE* f = fopen(pathToShader, "rb");

    if(!f)

        return NULL;

    fseek(f, 0, SEEK_END);

    size_t shaderLen = ftell(f);

    fseek(f, 0, SEEK_SET);

    GLchar* code = (GLchar*) malloc(shaderLen+1);

    fread(code, sizeof(char), shaderLen, f);

    fclose(f);

    code[shaderLen] = '\0';

    return code;

GLboolean loadShader(GLenum shaderType, const GLchar** shaderText, GLint* shaderID)

    GLint status = 0;

    *shaderID = glCreateShader(shaderType);

    glShaderSource(*shaderID, 1, shaderText, NULL);

    glCompileShader(*shaderID);

    glGetShaderiv(*shaderID, GL_COMPILE_STATUS, &status);

    if(status == GL_FALSE)

        GLint logLength = 0;

        glGetShaderiv(*shaderID, GL_INFO_LOG_LENGTH, &logLength);

        GLcharARB *log = (GLcharARB*) malloc(logLength);

        glGetShaderInfoLog(*shaderID, logLength, &logLength, log);

        printf("Shader compile log\n %s", log);

        free(log);

        return GL_FALSE;

    return GL_TRUE;

GLboolean linkShaders(GLint* program, GLint vertShaderID, GLint fragShaderID)

    GLint status = 0;

    *program = glCreateProgram();

    glAttachShader(*program, vertShaderID);

    glAttachShader(*program, fragShaderID);

    GLint logLength;

    glLinkProgram(*program);

    glGetProgramiv(*program, GL_INFO_LOG_LENGTH, &logLength);

    if (logLength > 0) {

        GLchar *log = (GLchar*) malloc(logLength);

        glGetProgramInfoLog(*program, logLength, &logLength, log);

        printf("Program link log:\n%s\n", log);

        free(log);

        glDeleteShader(vertShaderID);

        glDeleteShader(fragShaderID);

        return GL_FALSE;

    glValidateProgram(*program);

    glGetProgramiv(*program, GL_INFO_LOG_LENGTH, &logLength);

    if (logLength > 0) {

        GLchar *log = (GLchar*)malloc(logLength);

        glGetProgramInfoLog(*program, logLength, &logLength, log);

        printf("Program validate log:\n%s\n", log);

        free(log);

        return GL_FALSE;

    glGetProgramiv(*program, GL_VALIDATE_STATUS, &status);

    if (status == 0)

        printf("Failed to validate program %d\n", *program);

        return GL_FALSE;

    return GL_TRUE;

@end

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