Shader class

Shader

Note

LibGui has it's own build-in shaders, so if you don't need to have custom ones, you can just skip this part.

LibGui::Shader is wrapper for OpenGL shader programs, they are programs that run on GPU and calculate positions of vertexes and colors of individual pixels.

Warning

If you aren't familiar with shaders, please read this first.

Initialization

Initialization from file

To initialize from file you can simply do this:

LibGui::Shader MyShader("my_vertex_shader_source.txt", "my_fragment_shader_source.txt");

Initialization from source string

If you have string variable you want to create shader from, you can do this:

std::string vertex_source;
std::string fragment_source;

LibGui::Shader MyShader;
MyShader.Compile(vertex_source, fragment_source);

Methods

void Bind()

Binds shader.

boid Unbind()

Unbinds shader.

void Compile(...)

here

void CompileFromFile(...)

equivalent of this

unsigned int GetID()

Returns shader's OpenGL id.

Uniform setters

To set an uniform, you can call one of these:

	int	unsigned int	float
1 value	SetUniform1Int	SetUniform1UInt	SetUniform1Float
Vec2	SetUniformVec2i	SetUniform2UInt	SetUniformVec2
Vec3	SetUniform3Int	SetUniform3UInt	SetUniform3Float
Vec4	SetUniform4Int	SetUniform4UInt	SetUniform4Float

Debugging

If the shader can run, the compilationSuccessful property will be true. Otherwise the errors will be printed to console, and added to std::vector<std::string> compilationErrors.

Default shader's uniforms

Vertex shader uniforms

Name	Description
vec2 u_ParentPos	Object.pos; will be added to vertexes final coord
vec2 u_Scale	Object.scale; will be multiplied with vertexes local coord
vec2 u_RightVector	first half of rotation matrix (come on, we don't even have linear algebra at school yet)
vec2 u_UpVector	second half of rotation matrix
vec4 u_ParentPos	Object.color; will be multiplied with vertexes color

Fragment shader uniforms

Name	Desription
sampler2D myTexture	Object.texture
bool u_HasTexture	Object.texture!=nullptr
vec2 u_EdgeMin	Upper left corner of render mask
vec2 u_EdgeMax	Lower right corner of render mask