GLSL: Difference between revisions

(7 intermediate revisions by the same user not shown)

Line 1:

OpenGL Shading Language (GLSL) is the shader language used in OpenGL and WebGL.

Note that there are multiple versions of OpenGL such as 3, 4, ES

==Usage==

===Vertex Shader===

In the vertex shader, you position vertices by projecting them from object coordinates to camera coordinates.

This is typically done by multiplying each vertex position, passed as an attribute, with the MVP matrices, passed as a uniform.

Oftentimes you will also want to pass the UV coordinates to the fragment shader as a varying.

===Fragment Shader===

In the fragment shader, you will typically sample a base color and apply lighting to your object.

Sampling is typically done with <code>texture2D</code> which returns an interpolated and mipmaped color from your <code>sampler2D</code> texture.

==Pipeline==

See [https://www.khronos.org/opengl/wiki/Rendering_Pipeline_Overview OpenGL Rendering Pipeline Overview]

===Vertex Shader===

In the vertex shader, your inputs are a model matrix, view matrix, and projection matrix uniforms as well as one vertex position in local coordinates.

Line 15:

Line 28:

These values can be passed to the following stages as <code>varying</code>'s.

<code>varying</code>'s are linearly interpolated using barycentric coordinates.

===Tesselation Shader===

This is an optional shader which can be used to dynamically upsample your triangles using subdivision.

It typically runs once per triangle.

===Geometry Shader===

~~===Tesselation Shader===~~

This is an optional shader which can be used to generate or remove triangles.

It typically runs once per point, line, or triangle.

The outputs are typically new vertices and new triangles.

===Fragment Shader===

This shader outputs pixel color values based on information stored in each triangle.

It runs once per pixel.

==Resources==

===Reference cards===

* [https://www.khronos.org/files/opengl45-quick-reference-card.pdf OpenGL 4.5 Reference card]

* [https://www.khronos.org/opengles/sdk/docs/reference_cards/OpenGL-ES-2_0-Reference-card.pdf OpenGL ES 2.0 Reference card]

* [https://www.khronos.org/assets/uploads/developers/presentations/opengles31-quick-reference-card.pdf OpenGL ES 3.1 Reference card]

* [https://www.khronos.org/files/webgl/webgl-reference-card-1_0.pdf WebGL 1.0 Reference card]

* [https://www.khronos.org/files/webgl20-reference-guide.pdf WebGL 2.0 Reference card]

[[Category:Programming languages]]

[[Category:GPU Programming languages]]

@@ Line 1: / Line 1: @@
 OpenGL Shading Language (GLSL) is the shader language used in OpenGL and WebGL.
+Note that there are multiple versions of OpenGL such as 3, 4, ES
 ==Usage==
+===Vertex Shader===
+In the vertex shader, you position vertices by projecting them from object coordinates to camera coordinates.
+This is typically done by multiplying each vertex position, passed as an attribute, with the MVP matrices, passed as a uniform.
+Oftentimes you will also want to pass the UV coordinates to the fragment shader as a varying.
+===Fragment Shader===
+In the fragment shader, you will typically sample a base color and apply lighting to your object.
+Sampling is typically done with <code>texture2D</code> which returns an interpolated and mipmaped color from your <code>sampler2D</code> texture.
 ==Pipeline==
+See [https://www.khronos.org/opengl/wiki/Rendering_Pipeline_Overview OpenGL Rendering Pipeline Overview]
 ===Vertex Shader===
 In the vertex shader, your inputs are a model matrix, view matrix, and projection matrix uniforms as well as one vertex position in local coordinates.
@@ Line 15: / Line 28: @@
 These values can be passed to the following stages as <code>varying</code>'s.
 <code>varying</code>'s are linearly interpolated using barycentric coordinates.
+===Tesselation Shader===
+This is an optional shader which can be used to dynamically upsample your triangles using subdivision.
+It typically runs once per triangle.
 ===Geometry Shader===
-===Tesselation Shader===
+This is an optional shader which can be used to generate or remove triangles.
+It typically runs once per point, line, or triangle.
+The outputs are typically new vertices and new triangles.
 ===Fragment Shader===
+This shader outputs pixel color values based on information stored in each triangle.
+It runs once per pixel.
+==Resources==
+===Reference cards===
+* [https://www.khronos.org/files/opengl45-quick-reference-card.pdf OpenGL 4.5 Reference card]
+* [https://www.khronos.org/opengles/sdk/docs/reference_cards/OpenGL-ES-2_0-Reference-card.pdf OpenGL ES 2.0 Reference card]
+* [https://www.khronos.org/assets/uploads/developers/presentations/opengles31-quick-reference-card.pdf OpenGL ES 3.1 Reference card]
+* [https://www.khronos.org/files/webgl/webgl-reference-card-1_0.pdf WebGL 1.0 Reference card]
+* [https://www.khronos.org/files/webgl20-reference-guide.pdf WebGL 2.0 Reference card]
+[[Category:Programming languages]]
+[[Category:GPU Programming languages]]