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OpenGLRenderer.mm

/*

     File: OpenGLRenderer.mm

 Abstract: The renderer class creates and draws the OpenGL shaders. This is where we set up instancing and draw the set of gears with one single instancing draw call.

  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); \

} \

#define VS_NAME "vertexShaderFlat.vs"

#define FS_NAME "fragmentShaderFlat.fs"

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

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

@implementation OpenGLRenderer

- (void)loadTriangleToothedGearFlat

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

    triToothedGearFlat->vertCount = VERTEX_COUNT;

    triToothedGearFlat->indexCount = 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);

- (id)init

    if (self = [super init])

        [self loadTriangleToothedGearFlat];

        animationDelta = 1.5;

        animationStep = 0.0;

        kAnimationLoopValue = 360.0 / animationDelta;

        animate = YES;

        xAxisAngle = 0.0;

        zAxisAngle = 0.0;

    return self;

- (void)dealloc

    glFinish();

    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0);

    glBindBuffer(GL_ARRAY_BUFFER, 0);

    glDeleteBuffers(4, &triToothedGearFlat->vertsID);

    free(triToothedGearFlat);

    glDeleteBuffers(1, &scaleBufferID);

    glDeleteBuffers(1, &orientationMatID);

    glUseProgram(0);

    int i = 0;

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

        glDeleteProgram(programs[i]);

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

        glDeleteShader(shaders[i]);

    [super dealloc];

#pragma mark General Setup

- (BOOL)setupScene

    int nRows = 8;

    int nCols = 9;

    numGears = nRows * nCols;

    // create scaling factor and orientation per gear

    GLfloat* scaleBuffer = (GLfloat*) malloc(sizeof(GLfloat)*numGears);

    GLKMatrix4* orientationMat = (GLKMatrix4*) malloc(sizeof(GLKMatrix4)*numGears);

    GLKMatrix4 temp;

    float initialx = -2.0;

    float initialy = -2.0;

    int ndx = 0;

    for (int j = 0; j < nRows; j++) {

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

            // scaling per gear

            scaleBuffer[ndx] = 1.0/10.0 * ((j%2) ? 1.0 : 0.8);

            // orientation per gear

            temp = GLKMatrix4MakeTranslation(initialx+i*0.5, initialy+j*0.5, 3.0);

            if (i%2)

                temp = GLKMatrix4Rotate(temp, M_PI, 1.0, 0.0, 0.0);

            orientationMat[ndx] = temp;

            ndx ++;

    glGenBuffers(1, &scaleBufferID);

    glGenBuffers(1, &orientationMatID);

    // buffer all the scaling data into one VBO

    glBindBuffer(GL_ARRAY_BUFFER, scaleBufferID);

    glBufferData(GL_ARRAY_BUFFER, sizeof(GLfloat)*numGears, scaleBuffer, GL_STATIC_DRAW);

    glError();

    // buffer all the orientation matrices into one VBO

    glBindBuffer(GL_ARRAY_BUFFER, orientationMatID);

    glBufferData(GL_ARRAY_BUFFER, sizeof(GLKMatrix4)*numGears, orientationMat, GL_STATIC_DRAW);

    glError();

    free(scaleBuffer);

    free(orientationMat);

    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; lightColor.w = 1.0;

    return YES;

- (BOOL)setupGL

    // create a VAO (vertex array object)

    glGenVertexArrays(1, &gearVAOId);

    glBindVertexArray(gearVAOId);

    if([self loadShaders])

        return NO;

    if(![self setupScene])

        return NO;

    glEnable(GL_DEPTH_TEST);

    glEnable(GL_CULL_FACE);

    glViewport(0, 0, width, height);

    // set up the projection matrix uniform

    GLKMatrix4 projectionMatrix = GLKMatrix4MakePerspective(75.0 * (M_PI/180.0), ((GLdouble) width) / ((GLdouble) height), 0.1, 35.0);

    glUseProgram(programs[0]);

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

    // the gear's normals are with the first vertex

    glProvokingVertexEXT(GL_FIRST_VERTEX_CONVENTION_EXT);

    // set up vertex attributes

    // one scale and one matrix *per instance*

    glBindBuffer(GL_ARRAY_BUFFER, scaleBufferID);

    glVertexAttribPointer(attribScale, 1, GL_FLOAT, GL_FALSE, 0, NULL);

    // glVertexAttribDivisor modifies the rate at which generic vertex attributes advance during instanced rendering

    // here we specify that we want to advance the attribute once per instance

    glVertexAttribDivisorARB(attribScale, 1);

    // all matrix data is in one VBO. Set appropriate offsets

    glBindBuffer(GL_ARRAY_BUFFER, orientationMatID);

    glVertexAttribPointer(attribOrientationMatrix0, 4, GL_FLOAT, GL_FALSE, sizeof(GLKMatrix4), NULL);

    glVertexAttribDivisorARB(attribOrientationMatrix0, 1);

    glVertexAttribPointer(attribOrientationMatrix1, 4, GL_FLOAT, GL_FALSE, sizeof(GLKMatrix4), (const GLvoid*) (sizeof(GLKVector4)));

    glVertexAttribDivisorARB(attribOrientationMatrix1, 1);

    glVertexAttribPointer(attribOrientationMatrix2, 4, GL_FLOAT, GL_FALSE, sizeof(GLKMatrix4), (const GLvoid*) (2*sizeof(GLKVector4)));

    glVertexAttribDivisorARB(attribOrientationMatrix2, 1);

    glVertexAttribPointer(attribOrientationMatrix3, 4, GL_FLOAT, GL_FALSE, sizeof(GLKMatrix4), (const GLvoid*) (3*sizeof(GLKVector4)));

    glVertexAttribDivisorARB(attribOrientationMatrix3, 1);

    // position, color and normal *per vertex*

    glBindBuffer(GL_ARRAY_BUFFER, triToothedGearFlat->vertsID);

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

    glBindBuffer(GL_ARRAY_BUFFER, triToothedGearFlat->colorsID);

    glVertexAttribPointer(attribColor, 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);

    [self regenCameraMatrix];

    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;

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

    GLKVector4 lightPosition = GLKMatrix4MultiplyVector4(cameraMatrix, lightPos);

    glClearColor(1.0, 1.0, 1.0, 1.0);

    glClear(GL_DEPTH_BUFFER_BIT | GL_COLOR_BUFFER_BIT);

    glBindVertexArray(gearVAOId);

    // enable all our attribs

    glEnableVertexAttribArray(attribPosition);

    glEnableVertexAttribArray(attribColor);

    glEnableVertexAttribArray(attribNormal);

    glEnableVertexAttribArray(attribScale);

    // matrices are 4 sequential attribs, each is a column

    glEnableVertexAttribArray(attribOrientationMatrix0);

    glEnableVertexAttribArray(attribOrientationMatrix1);

    glEnableVertexAttribArray(attribOrientationMatrix2);

    glEnableVertexAttribArray(attribOrientationMatrix3);

    // update uniform vals

    glUseProgram(programs[0]);

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

    glUniformMatrix4fv(rotationAnimationMatrixLocation, 1, GL_FALSE, (const GLfloat*) &rotMatrix);

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

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

    // call glDrawElementsInstanced to render multiple instances of primitives in a single draw call

    glDrawElementsInstancedARB(GL_TRIANGLES, triToothedGearFlat->indexCount, GL_UNSIGNED_INT, NULL, numGears);

    glUseProgram(0);

    glBindVertexArray(0);

- (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

- (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;

- (GLshort)loadShaders

    GLchar* shader = [self loadShaderFromFile:VS_NAME];

    if (!shader) {

        return 1;

    if(!loadShader(GL_VERTEX_SHADER, (const GLchar**) &shader, &shaders[0]))

        return 1;

    free(shader);

    shader = [self loadShaderFromFile:FS_NAME];

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

        return 2;

    free(shader);

    if(!linkShaders(&programs[0], shaders[0], shaders[1]))

        return 3;

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

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

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

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

    attribOrientationMatrix0 = glGetAttribLocation(programs[0], "attribOrientationMatrix");

    attribOrientationMatrix1 = attribOrientationMatrix0+1;

    attribOrientationMatrix2 = attribOrientationMatrix1+1;

    attribOrientationMatrix3 = attribOrientationMatrix2+1;

    rotationAnimationMatrixLocation = glGetUniformLocation(programs[0], "rotationAnimationMatrix");

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

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

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

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

    glError();

    return 0;

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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