iglu.core

(iglu->glsl shader)

(iglu->glsl shader-type shader)

Converts an iglu map into a GLSL string. The second arity is only for backwards compatibility and should not be used.

Examples

A simple vertex shader.
"#version 300 es\nuniform mat4 u_matrix;\nin vec4 a_position;\nin vec4 a_color;\nout vec4 v_color;\nvoid main()\n{\n gl_Position = (a_position * u_matrix);\n v_color = a_color;\n}"
(iglu->glsl '{:version "300 es", :uniforms {u_matrix mat4}, :inputs {a_position vec4, a_color vec4}, :outputs {v_color vec4}, :signatures {main ([] void)}, :functions {main ([] (= gl_Position (* a_position u_matrix)) (= v_color a_color))}})
A simple fragment shader.
"#version 300 es\nprecision mediump float;\nin vec4 v_color;\nout vec4 outColor;\nvoid main()\n{\n outColor = v_color;\n}"
(iglu->glsl '{:version "300 es", :precision "mediump float", :inputs {v_color vec4}, :outputs {outColor vec4}, :signatures {main ([] void)}, :functions {main ([] (= outColor v_color))}})
A vertex shader with a user-defined function.
"#version 300 es\nuniform mat4 u_matrix;\nin vec4 a_position;\nin vec4 a_color;\nout vec4 v_color;\nvec4 multiply(mat4 x, vec4 y)\n{\n return x * y;\n}\nvoid main()\n{\n gl_Position = (multiply(u_matrix, a_position));\n v_color = a_color;\n}"
(iglu->glsl '{:version "300 es", :uniforms {u_matrix mat4}, :inputs {a_position vec4, a_color vec4}, :outputs {v_color vec4}, :signatures {multiply ([mat4 vec4] vec4), main ([] void)}, :functions {multiply ([x y] (* x y)), main ([] (= gl_Position (multiply u_matrix a_position)) (= v_color a_color))}})
Strings are passed through without modification. This is generally what you want for GLSL keywords and floating point numbers.
"#version 300 es\nprecision mediump float;\nuniform sampler2D u_image;\nin vec2 v_texCoord;\nout vec4 outColor;\nvoid main()\n{\n outColor = (texture(u_image, v_texCoord));\n if ((outColor.rgb) == (vec3(0.0, 0.0, 0.0)))\n {\n discard;\n }\n else\n {\n outColor = (vec4(0.0, 0.0, 0.0, 1.0));\n }\n}"
(iglu->glsl '{:version "300 es", :precision "mediump float", :uniforms {u_image sampler2D}, :inputs {v_texCoord vec2}, :outputs {outColor vec4}, :signatures {main ([] void)}, :functions {main ([] (= outColor (texture u_image v_texCoord)) ("if" (== (.rgb outColor) (vec3 "0.0" "0.0" "0.0")) "discard") ("else" (= outColor (vec4 "0.0" "0.0" "0.0" "1.0"))))}})
A vertex shader that loops over a uniform array.
"#version 300 es\nuniform mat3 u_matrix;\nuniform int[1000] u_char_counts;\nin vec2 a_position;\nin vec4 a_color;\nout vec4 v_color;\nvoid main()\n{\n int total_char_count = 0;\n int current_line = 0;\n for (int i=0; i<1000; ++i)\n {\n total_char_count += u_char_counts[i];\n if (total_char_count > gl_InstanceID)\n {\n break;\n }\n else\n {\n current_line += 1;\n }\n }\n mat3 matrix = u_matrix;\n matrix[2][1] *= current_line;\n gl_Position = (vec4(((matrix * (vec3(a_position, 1))).xy), 0, 1));\n v_color = a_color;\n}"
(iglu->glsl '{:version "300 es", :uniforms {u_matrix mat3, u_char_counts [int 1000]}, :inputs {a_position vec2, a_color vec4}, :outputs {v_color vec4}, :signatures {main ([] void)}, :functions {main ([] (=int total_char_count 0) (=int current_line 0) ("for (int i=0; i<1000; ++i)" (+= total_char_count [u_char_counts i]) ("if" (> total_char_count gl_InstanceID) "break") ("else" (+= current_line 1))) (=mat3 matrix u_matrix) (*= [matrix 2 1] current_line) (= gl_Position (vec4 (.xy (* matrix (vec3 a_position 1))) 0 1)) (= v_color a_color))}})
As an escape hatch, you may optionally write your functions in GLSL.
"#version 300 es\nin vec2 a_position;\nout vec4 v_color;\n\nvoid main()\n{\n gl_Position = vec4(a_position.x, a_position.y, 0.0, 1.0);\n v_color = gl_Position * 0.5 + 0.5;\n}"
(iglu->glsl '{:version "300 es", :inputs {a_position vec2}, :outputs {v_color vec4}, :functions "\nvoid main()\n{\n gl_Position = vec4(a_position.x, a_position.y, 0.0, 1.0);\n v_color = gl_Position * 0.5 + 0.5;\n}"})

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