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C-/C++-Quelltext

glGenRenderbuffersEXT(1, &depthBuffer);
    glBindRenderbufferEXT(GL_RENDERBUFFER_EXT, depthBuffer);
    glRenderbufferStorageEXT(GL_RENDERBUFFER_EXT, GL_DEPTH_COMPONENT24, width, height);
    glBindFramebufferEXT(GL_FRAMEBUFFER_EXT, fbo);
    glFramebufferRenderbufferEXT(GL_FRAMEBUFFER_EXT, GL_DEPTH_ATTACHMENT_EXT, GL_RENDERBUFFER_EXT, depthBuffer);

C-/C++-Quelltext

glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_COMPARE_FUNC, GL_LEQUAL);
    glTexParameteri(GL_TEXTURE_2D, GL_DEPTH_TEXTURE_MODE, GL_LUMINANCE);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_COMPARE_MODE, GL_COMPARE_R_TO_TEXTURE);

C-/C++-Quelltext

glGenTextures(1, &shadowMap); // Textur
    glBindTexture(GL_TEXTURE_2D, shadowMap);

    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
    glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
    glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);

    glTexImage2D(GL_TEXTURE_2D, 
                 0,
                 GL_DEPTH_COMPONENT,
                 windowSize[0], 
                 windowSize[1],
                 0,
                 GL_DEPTH_COMPONENT, 
                 GL_UNSIGNED_BYTE, 
                 NULL);

    glGenFramebuffers(1, &shadowFBO); // FBO
    glBindFramebuffer(GL_FRAMEBUFFER, shadowFBO);

    glFramebufferTexture2D(GL_FRAMEBUFFER, 
                           GL_DEPTH_ATTACHMENT,
                           GL_TEXTURE_2D, 
                           shadowMap,
                           0);

    glDrawBuffer(GL_NONE);
    glReadBuffer(GL_NONE);
        
    if(glCheckFramebufferStatus(GL_FRAMEBUFFER) != GL_FRAMEBUFFER_COMPLETE){
        cerr<<"Framebuffer could not be initalized!"<<endl;
    }

    glBindFramebuffer(GL_FRAMEBUFFER, 0);

C-/C++-Quelltext

void renderShadowMap(){
    glEnableVertexAttribArray(0); // Vertex

    for(unsigned int i = 0;  i < objects.size(); i++){      
        glPushMatrix();         

        glScalef(objects[i]->getScale(), objects[i]->getScale(), objects[i]->getScale());
        glTranslatef(objects[i]->getX(), objects[i]->getY(), objects[i]->getZ());
        glRotatef(objects[i]->getXRotation(), 1, 0, 0);
        glRotatef(objects[i]->getYRotation(), 0, 1, 0);
        glRotatef(objects[i]->getZRotation(), 0, 0, 1);
                                
        glBindBuffer(GL_ARRAY_BUFFER, objects[i]->getVertexBuffer());
        glVertexAttribPointer(GLint(0), 3, GL_FLOAT, GL_FALSE, 0, 0);
    
        glDrawArrays(GL_TRIANGLES, 0, objects[i]->getVerticesNumber());

        glPopMatrix();
    }

    glDisableVertexAttribArray(0);
}

C-/C++-Quelltext

// Matrizen

void setShadowMatrix(){
    float modelview[16];
    float projection[16];
    float bias[16] = {0.5, 0.0, 0.0, 0.0, 
                      0.0, 0.5, 0.0, 0.0,
                      0.0, 0.0, 0.5, 0.0,
                      0.5, 0.5, 0.5, 1.0};

    glGetFloatv(GL_MODELVIEW_MATRIX, modelview);
    glGetFloatv(GL_MODELVIEW_MATRIX, projection);

    for(unsigned int i = 0; i < 16; i++){
        shadowMatrix[i] = bias[i]*projection[i]*modelview[i];
    }
}

// Perspective

gluPerspective(45, 1.0*windowSize[0]/windowSize[1], 2, 100);

// Vertex

uniform mat4 projection_matrix;
uniform mat4 modelview_matrix;
uniform mat4 shadow_matrix0;

in vec3 a_Vertex;
in vec2 a_TexCoord0;

out vec2 texCoord0;
out vec4 shadowCoord;

void main(void){    
    shadowCoord = shadow_matrix0*modelview_matrix*vec4(a_Vertex, 1.0);
    texCoord0 = a_TexCoord0;
    gl_Position = projection_matrix*(modelview_matrix*vec4(a_Vertex, 1.0));     
}

// Fragment

precision highp float;

uniform sampler2D texture0;
uniform sampler2D shadowMap0;

in vec4 shadowCoord;
in vec2 texCoord0;

out vec4 outColor;

void main(void){    
    outColor = texture(texture0, texCoord0.xy);

    // Shadow mapping
    vec3 scWdevide = shadowCoord.xyz/shadowCoord.w;
    scWdevide.z += 0.0005;

    float depth = texture(shadowMap0, scWdevide.st).w;

    float shadow = 1.0;
    if(shadowCoord.w > 0.0){
        shadow = (depth < scWdevide.z) ? 0.5 : 1.0;
    }

    outColor *= shadow;
}