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OpenGLRenderer.mm

/*

     File: OpenGLRenderer.mm

 Abstract: The renderer class creates and draws the OpenGL shaders. Here we provide an example of two-dimensional texture array. It visualizes a terrain by using terrain's Z-coordinate to index into a texture array and applies the correct image for that point's elevation.

  Version: 1.3

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*/

#import "OpenGLRenderer.h"

#include "GeoUtils.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 "HeightArray.vs"

#define FS_NAME "HeightArray.fs"

#define TEXTURE0 "rock.jpg"

#define TEXTURE1 "grass.jpg"

#define TEXTURE2 "dirt.jpg"

#define TEXTURE3 "snow.jpg"

const uint32_t kHeightMapDefaultSize = 64;

typedef struct {

    uint32_t wide;

    uint32_t high;

    GLenum format;

    GLenum type;

    void* data;

} textureInfo_t;

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])

        xAxisAngle = -45.0 * (M_PI/180.0);

        zAxisAngle = 43.0 * (M_PI/180.0);

        iHeightMapSize = kHeightMapDefaultSize;

    return self;

- (void)dealloc

    glFinish();

    glBindVertexArray(0);

    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0);

    glBindBuffer(GL_ARRAY_BUFFER, 0);

    glDeleteBuffers(iHeightMapSize, terrain);

    glDeleteVertexArrays(1, &vaoId);

    glDeleteTextures(1, &texId);

    glUseProgram(0);

    int i = 0;

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

        glDeleteProgram(programs[i]);

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

        glDeleteShader(shaders[i]);

    free(map);

    free(terrain);

    [super dealloc];

- (BOOL)setupScene

    glGenVertexArrays(1, &vaoId);

    glBindVertexArray(vaoId);

    //You can play around with the terrain generation here...

    map = GenHeightMap(iHeightMapSize, iHeightMapSize, 0xDEADBEEF);

    //map = GenHeightMap(iHeightMapSize, iHeightMapSize, 0xBEEFBEEF);

    terrain = (GLuint*) malloc(sizeof(GLuint)*iHeightMapSize);

    size_t bufsize = iHeightMapSize*12*sizeof(GLfloat);

    glGenBuffers(iHeightMapSize-1, terrain);

    //now let's load this heightmap into buffer objects

    int i, j;

    for (j = 0; j < iHeightMapSize-1; j++)

        glBindBuffer(GL_ARRAY_BUFFER, terrain[j]);

        //allocate enough space in VRAM

        glBufferData(GL_ARRAY_BUFFER, bufsize, NULL, GL_STATIC_DRAW);

        //map the VBO into client memory and fill it

        float* buf = (float*) glMapBuffer(GL_ARRAY_BUFFER, GL_WRITE_ONLY);

/*

         NOTE:

         The map buffer has 6 floats per vertex, position and normal

         This loads the terrain in, as vertical slices (think a cross section)

         We load from the current row and row+1 to fill out the tristrips

*/

        for (i = 0; i < iHeightMapSize; i++)

            int ndx = i*12;

            memcpy(&buf[ndx]  , &map[( j   *iHeightMapSize + i)*6]  , sizeof(GLfloat)*6);

            memcpy(&buf[ndx+6], &map[( (j+1) *iHeightMapSize + i)*6]  , sizeof(GLfloat)*6);

        glUnmapBuffer(GL_ARRAY_BUFFER);

    return YES;

- (BOOL)loadTextureArray

    textureInfo_t tex0, tex1, tex2, tex3;

    if(![self loadTexture:&tex0 fromFile:TEXTURE0])

        return NO;

    if(![self loadTexture:&tex1 fromFile:TEXTURE1])

        return NO;

    if(![self loadTexture:&tex2 fromFile:TEXTURE2])

        return NO;

    if(![self loadTexture:&tex3 fromFile:TEXTURE3])

        return NO;

    glError();

    glPixelStorei(GL_UNPACK_ALIGNMENT, 1);

    glPixelStorei(GL_PACK_ALIGNMENT, 1);

    //send textures to GPU

    glGenTextures(1, &texId);

    glBindTexture(GL_TEXTURE_2D_ARRAY, texId);

    glTexParameteri(GL_TEXTURE_2D_ARRAY, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR);

    glTexParameteri(GL_TEXTURE_2D_ARRAY, GL_TEXTURE_MAG_FILTER, GL_LINEAR);

    glTexImage3D(GL_TEXTURE_2D_ARRAY, 0, GL_RGB8, tex0.wide, tex0.high, 4, 0, tex0.format, tex0.type, NULL);

    glGenerateMipmap(GL_TEXTURE_2D_ARRAY);

    // Note: these images must have the same size and format to be able to loaded into a texture array

    glTexSubImage3D(GL_TEXTURE_2D_ARRAY, 0, 0, 0, 0, tex0.wide, tex0.high, 1, tex0.format, tex0.type, tex0.data);

    glTexSubImage3D(GL_TEXTURE_2D_ARRAY, 0, 0, 0, 1, tex0.wide, tex0.high, 1, tex0.format, tex0.type, tex1.data);

    glTexSubImage3D(GL_TEXTURE_2D_ARRAY, 0, 0, 0, 2, tex0.wide, tex0.high, 1, tex0.format, tex0.type, tex2.data);

    glTexSubImage3D(GL_TEXTURE_2D_ARRAY, 0, 0, 0, 3, tex0.wide, tex0.high, 1, tex0.format, tex0.type, tex3.data);

    free(tex0.data);

    free(tex1.data);

    free(tex2.data);

    free(tex3.data);

    glError();

    return YES;

- (BOOL)setupGL

    if(![self setupScene])

        return NO;

    if([self loadShaders])

        return NO;

    if (![self loadTextureArray])

        return NO;

    glViewport(0, 0, width, height);

    glClearColor(0.3, 0.4, 0.5, 1.0);

    glEnable(GL_DEPTH_TEST);

    //set up a default camera matrix

    [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

    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

    // compute an appropriate projection matrix

    GLKMatrix4 projectionMatrix = GLKMatrix4MakePerspective(60.0 * (M_PI/180.0), ((GLdouble) width) / ((GLdouble) height), 1.0, 100.0);

    // and texture matrix

    GLKMatrix4 m = GLKMatrix4MakeTranslation(0.0, 0.0, -0.5);

    m = GLKMatrix4Scale(m, 1.0, 1.0, 4.0);

    m = GLKMatrix4Scale(m, 1.0/iHeightMapSize, 1.0/iHeightMapSize, 1.0/16.0);

    GLKMatrix4 textureMatrix = GLKMatrix4Translate(m, 0.0, 0.0, 8.0);

    // draw simple 3D terrain

    glUseProgram(programs[0]);

    glActiveTexture(GL_TEXTURE0);

    glBindTexture(GL_TEXTURE_2D_ARRAY, texId);

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

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

    glUniformMatrix4fv(textureMatrixLocation, 1, GL_FALSE, (const GLfloat*) &textureMatrix);

    glUniform1i(samplerLocation, 0);

/*

     NOTE:

     For optimal performance, you probably want Frustum-culled patches or something similar, instead of always

     drawing strips of terrain as this sample does.

*/

    glEnableVertexAttribArray(attribPosition);

    glEnableVertexAttribArray(attribTexCoord);

    glEnableVertexAttribArray(attribNormal);

    int j;

    for (j = 0; j < iHeightMapSize-1; j++)

        glBindBuffer(GL_ARRAY_BUFFER, terrain[j]);

        glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0);

        glVertexAttribPointer(attribPosition, 3, GL_FLOAT, GL_FALSE, sizeof(GLfloat)*6, NULL);

        // we use the vertex positions as 3D texture coordinates too to index into the 2D texture array

        glVertexAttribPointer(attribTexCoord, 3, GL_FLOAT, GL_FALSE, sizeof(GLfloat)*6, NULL);

        glVertexAttribPointer(attribNormal, 3, GL_FLOAT, GL_FALSE, sizeof(GLfloat)*6, (const GLvoid*) (sizeof(GLfloat)*3));

        glDrawArrays(GL_TRIANGLE_STRIP, 0, iHeightMapSize*2);

    glUseProgram(0);

#pragma mark Camera Utility

- (void)regenCameraMatrix

    // set up a default camera matrix

    GLKMatrix4 modelView = GLKMatrix4MakeTranslation(0, 0, -2.25);

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

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

    cameraMatrix = GLKMatrix4Scale(modelView, 2.0/iHeightMapSize, 2.0/iHeightMapSize, 4.0/iHeightMapSize);

- (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 Texture Loading

- (BOOL)loadTexture:(textureInfo_t*)texture fromFile:(const char*) filename

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

    CFStringRef string = CFStringCreateWithFormat(kCFAllocatorDefault, NULL, CFSTR("%s/%s"), resourcePath, filename);

    CFURLRef url = CFURLCreateWithFileSystemPath(kCFAllocatorDefault, string, kCFURLPOSIXPathStyle, false);

    CGImageSourceRef imageSource = CGImageSourceCreateWithURL(url, nil);

    CGImageRef image = CGImageSourceCreateImageAtIndex(imageSource, 0, nil);

    CFRelease(string);

    CFRelease(url);

    texture->wide = CGImageGetWidth(image);

    texture->high = CGImageGetHeight(image);

    GLint bpr = CGImageGetBytesPerRow(image);

    //if you want more info about the texture, look at these values

    //  CGBitmapInfo info = CGImageGetBitmapInfo(image);

    //  GLint bpp = CGImageGetBitsPerPixel(image);

    size_t numBytes = bpr * (texture->high);

    texture->format = GL_RGBA;

    texture->type = GL_UNSIGNED_BYTE;

    // get copy of raw uncompressed data

    CGDataProviderRef provider = CGImageGetDataProvider(image);

    CFDataRef dataref = CGDataProviderCopyData(provider);

    texture->data = malloc(numBytes);

    memcpy(texture->data, CFDataGetBytePtr(dataref), numBytes);

    CFRelease(dataref);

    CGImageRelease(image);

    CFRelease(imageSource);

    return YES;

#pragma mark Shader Loading

- (GLshort)loadShaders

    // vertex shader

    GLchar* shader = [self loadShaderFromFile:VS_NAME];

    if (!shader) {

        return 1;

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

        return 1;

    free(shader);

    // fragment shader

    shader = [self loadShaderFromFile:FS_NAME];

    if (!shader) {

        return 2;

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

            return 2;

    free(shader);

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

        return 3;

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

    textureMatrixLocation = glGetUniformLocation(programs[0], "textureMatrix");

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

    samplerLocation = glGetUniformLocation(programs[0], "sampler");

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

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

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

    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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