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Updated raylib generic uber shader and custom shaders (markdown)

Ray
2020-01-09 11:18:09 +01:00
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raylib-generic-uber-shader-and-custom-shaders.md

@ -1,16 +1,16 @@
Dealing with custom shaders and making them generic is not an easy task. There are many things to consider for a shader because, after all, the shader is responsible for processing all the data sent to the GPU (mesh, materials, textures, lighting) to generate the final frame. Dealing with custom shaders and making them generic is not an easy task. There are many things to consider for a shader because, after all, shaders are responsible for processing all the data sent to the GPU (mesh, materials, textures, lighting) to generate the final frame.
Finding a unified generic shader to deal with all kinds of stuff is very complicated and, after analyzing some of the big engines out there, I decided to go for a custom uber-shader-based solution. Finding a unified generic shader to deal with all kinds of stuff is very complicated so, after analyzing some of the big engines out there, I decided to go for a custom uber-shader-based solution.
By default, raylib's shader struct is defined as: By default, raylib's shader struct is defined as:
```c ```c
typedef struct Shader { typedef struct Shader {
unsigned int id; // Shader program id unsigned int id; // Shader program id
int locs[MAX_SHADER_LOCATIONS]; // Shader locations array int *locs; // Shader locations array (MAX_SHADER_LOCATIONS)
} Shader; } Shader;
``` ```
This struct provides an array to store shader locations, those locations can be accessed by position using predefined values for convenience: This struct provides an array to store shader locations, those locations can be accessed by position using predefined enum values for convenience:
```c ```c
// Shader location point type // Shader location point type
typedef enum { typedef enum {
@ -45,7 +45,7 @@ typedef enum {
#define LOC_MAP_SPECULAR LOC_MAP_METALNESS #define LOC_MAP_SPECULAR LOC_MAP_METALNESS
``` ```
On shader loading, the following location names are checked: On shader loading, the following GLSL location names are checked:
```glsl ```glsl
uniform mat4 mvp; // VS: ModelViewProjection matrix uniform mat4 mvp; // VS: ModelViewProjection matrix
uniform mat4 projection; // VS: Projection matrix uniform mat4 projection; // VS: Projection matrix
@ -58,17 +58,15 @@ uniform sampler2D texture2; // FS: GL_TEXTURE2
Shaders are also directly related to the Material struct: Shaders are also directly related to the Material struct:
```c ```c
// Material type
typedef struct Material {
// Material type (generic) // Material type (generic)
typedef struct Material { typedef struct Material {
Shader shader; // Material shader Shader shader; // Material shader
MaterialMap maps[MAX_MATERIAL_MAPS]; // Material maps MaterialMap *maps; // Material maps array (MAX_MATERIAL_MAPS)
float *params; // Material generic parameters (if required) float *params; // Material generic parameters (if required)
} Material; } Material;
``` ```
Material support by default a number of maps (texture and properties) that can be accessed for convenience using the provided values: Material supports by default a number of maps (texture and properties) that can be accessed for convenience using the provided values:
```c ```c
// Material map type // Material map type
@ -94,8 +92,8 @@ When drawing, maps are internally bound or not depending on the availability:
```c ```c
// Default material loading example // Default material loading example
Material material = LoadMaterialDefault(); // Default shader assigned to material Material material = LoadMaterialDefault(); // Default shader assigned to material
material.maps[MAP_DIFFUSE] = LoadTexture("tex_diffuse.png"); // texture unit 0 activated (available in material shader) material.maps[MAP_DIFFUSE].texture = LoadTexture("tex_diffuse.png"); // texture unit 0 activated (available in material shader)
material.maps[MAP_SPECULAR] = LoadTexture("tex_specular.png"); // texture unit 1 activated (available in material shader) material.maps[MAP_SPECULAR].texture = LoadTexture("tex_specular.png"); // texture unit 1 activated (available in material shader)
``` ```
User can load any custom shader using provided `Material` and `Shader`structs: User can load any custom shader using provided `Material` and `Shader`structs:
@ -108,7 +106,7 @@ material.shader = LoadShader("custom_shader.vs", "custom_shader.fs");
// Setup location points in case names are not predefined ones or more locations are required // Setup location points in case names are not predefined ones or more locations are required
// Use: GetShaderLocation() and SetShaderValue*() functions // Use: GetShaderLocation() and SetShaderValue*() functions
material.maps[0] = LoadTexture("tex_albedo.png"); material.maps[0].texture = LoadTexture("tex_albedo.png");
material.maps[1] = LoadTexture("tex_metalness.png"); material.maps[1].texture = LoadTexture("tex_metalness.png");
material.maps[2] = LoadTexture("tex_normal.png"); material.maps[2].texture = LoadTexture("tex_normal.png");
``` ```