cube-game-plus-plus/engine/shader/WorldShadowShader.cpp

#include "WorldShadowShader.h"
#include "../Wrapper.h"

WorldShadowShader::WorldShadowShader()
{
}

WorldShadowShader::~WorldShadowShader()
{
    glDeleteFramebuffers(1, &framebuffer);
    glDeleteTextures(1, &depthTexture);
}

bool WorldShadowShader::init()
{
    program.compile("shader/worldShadowVertex.vs", "shader/worldShadowFragment.fs");
    if(!program.isValid())
    {
        return false;
    }
    
    // generate framebuffer
    glGenFramebuffers(1, &framebuffer);
    glBindFramebuffer(GL_FRAMEBUFFER, framebuffer);
    glDrawBuffer(GL_NONE);
    glReadBuffer(GL_NONE);
        
    // depth texture
    glGenTextures(1, &depthTexture);
    glBindTexture(GL_TEXTURE_2D, depthTexture);
    glTexImage2D(GL_TEXTURE_2D, 0, GL_DEPTH_COMPONENT32, Engine::getWidth(), Engine::getHeight(), 0, GL_DEPTH_COMPONENT, GL_FLOAT, NULL);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_COMPARE_MODE, GL_COMPARE_REF_TO_TEXTURE);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_COMPARE_FUNC, GL_LEQUAL);
    // attache depth texture to framebuffer
    glFramebufferTexture2D(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_TEXTURE_2D, depthTexture, 0); 
    
    // check if framebuffer is okay
    if(glCheckFramebufferStatus(GL_FRAMEBUFFER) != GL_FRAMEBUFFER_COMPLETE)
    {
	cout << "world shadow frame buffer is not complete!" << endl;
        return false;
    }
    // unbind framebuffer
    glBindFramebuffer(GL_FRAMEBUFFER, 0);
    
    // get uniform locations
    unifProjMatrix = glGetUniformLocation(program.getProgram(), "projMatrix");
    unifViewMatrix = glGetUniformLocation(program.getProgram(), "viewMatrix");
    unifModelMatrix = glGetUniformLocation(program.getProgram(), "modelMatrix");
    
    return true;
}

void WorldShadowShader::resize()
{
    glBindTexture(GL_TEXTURE_2D, depthTexture);
    glTexImage2D(GL_TEXTURE_2D, 0, GL_DEPTH24_STENCIL8, Engine::getWidth(), Engine::getHeight(), 0, GL_DEPTH_STENCIL, GL_UNSIGNED_INT_24_8, NULL);
}

void WorldShadowShader::preRender(const float* projMatrix)
{
    // bind world shadow shader program
    glUseProgram(program.getProgram());
    
    // set projection matrix uniform
    glUniformMatrix4fv(unifProjMatrix, 1, 0, projMatrix);

    // bind world framebuffer
    glBindFramebuffer(GL_FRAMEBUFFER, framebuffer);
    
    // clear color, depth and stencil buffer
    glClear(GL_DEPTH_BUFFER_BIT | GL_STENCIL_BUFFER_BIT);
    
    // no color, depth testing is needed
    glEnable(GL_DEPTH_TEST);
}

void WorldShadowShader::bindDepthTexture(unsigned int textureUnit)
{
    glActiveTexture(GL_TEXTURE0 + textureUnit);
    glBindTexture(GL_TEXTURE_2D, depthTexture);
}

void WorldShadowShader::setViewMatrix(const float* data)
{
    glUniformMatrix4fv(unifViewMatrix, 1, 0, data);
}

void WorldShadowShader::setModelMatrix(const float* data)
{
    glUniformMatrix4fv(unifModelMatrix, 1, 0, data);
}