[SOLVED] Using shaders with sfml

[taifun93]

Hi!

I want to use this shader but all i get is a black image. I know the texture is loaded correctly because i can render it without the shader.

This is how i load and use the shader, which is probably not correct.

void init() {
        shader.loadFromFile("glsl-shaders-master/xbr/shaders/xbr-mlv4-multipass/xbr-mlv4-pass1.glsl", sf::Shader::Vertex);
        shader.loadFromFile("glsl-shaders-master/xbr/shaders/xbr-mlv4-multipass/xbr-mlv4-pass1.glsl", sf::Shader::Fragment);
        shader.setUniform("MVPmatrix", sf::Glsl::Mat4(bg_sprite.getTransform()));
        shader.setUniform("FrameDirection", 1);
        shader.setUniform("FrameCount", 100);
        shader.setUniform("OutputSize", sf::Vector2f(500, 500));
        shader.setUniform("TextureSize", sf::Vector2f(500, 500));
        shader.setUniform("InputSize", sf::Vector2f(500, 500));
        shader.setUniform("Texture", sf::Shader::CurrentTexture);

        //more code
}

void draw() {
        window.draw(bg_sprite, &shader);

        //more code
}

This are the errors i get:

Uniform "MVPmatrix" not found in shader
Uniform "FrameDirection" not found in shader
Uniform "FrameCount" not found in shader
Uniform "OutputSize" not found in shader
Uniform "TextureSize" not found in shader
Uniform "InputSize" not found in shader
Uniform "Texture" not found in shader

[Stauricus]

I'm a complete ignorant in shaders, but have you tried anothe one, just for testing? I get this error:

Failed to compile vertex shader:
0:368(1): error: syntax error, unexpected end of file

[taifun93]

I'm a complete ignorant in shaders, but have you tried anothe one, just for testing? I get this error:

Failed to compile vertex shader:
0:368(1): error: syntax error, unexpected end of file

I could use this simple shader which is not useful to me, it only paints some colors on top of everything. But other shaders that i downloaded do not seem to work.

uniform vec2 u_resolution;

void main() {
    vec2 st = gl_FragCoord.st/u_resolution;
    gl_FragColor = vec4(st.x, st.y, 0.0, 1);
}
 

        shader.loadFromFile("rainbow.glsl", sf::Shader::Fragment);
        shader.setUniform("u_resolution", sf::Glsl::Vec2{ 100, 100 });*/
 

[eXpl0it3r]

Since the linked shader has a big #if around the main body, I wonder whether the version check fails and thus you get no main() function which the compiler expects and as it doesn't find it until the end of the file, it errors with said message.

[Stauricus]

Since the linked shader has a big #if around the main body, I wonder whether the version check fails and thus you get no main() function which the compiler expects and as it doesn't find it until the end of the file, it errors with said message.

agreed. thats also why its not finding the variables.

[taifun93]

I made some progress. If i add this line the the shader file i get a green texture. I also dropped all the setUniform() calls from my program as they seem to do nothing.

#define FRAGMENT

[Stauricus]

well, 'setuniform' is used to pass variables from SFML to the shader... 

[taifun93]

I finally got it working! I had to separate the shader in two different files, one for the vertex shader and one for the fragment shader.

I also had to feed OutputSize, TextureSize, and InputSize uniform variables to the verex shader. Then in the main() function of the vertex shader i added these lines and delete their previous declarations.

        mat4 MVPMatrix = gl_ModelViewProjectionMatrix;
        vec4 VertexCoord = gl_Vertex;
        vec4 TexCoord = gl_TextureMatrix[0] * gl_MultiTexCoord0;