OpenGL pixel shader: Difference between revisions
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→{{header|Wren}}: Minor tidy
(→{{header|Go}}: Changed some integer literals in fragment shader to float. Wasn't compiling before.) |
m (→{{header|Wren}}: Minor tidy) |
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Line 11:
{{libheader|GLUT}}
Getting a true (pseudo) random number is surprisingly tricky. The following code makes something noisy, but not at all random:[[image:pixel_shader_C.png|right]]
<
#include <stdlib.h>
#include <GL/glew.h>
Line 86:
return 0;
}</
=={{header|Go}}==
Line 94:
<br>
The following uses 'cgo' to bind to the above C libraries. As C macro functions cannot be invoked directly from Go code, it has been necessary to wrap them first in 'normal' C functions and then invoke those.
<
/*
Line 227:
setShader()
C.glutMainLoop()
}</
=={{header|JavaScript}}
===(WebGL)===
<syntaxhighlight lang="javascript"><html style="margin: 0;">
<head>
<title>Fragment Shader WebGL Example</title>
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</script>
</body>
</html></
=={{header|Kotlin}}==
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</pre>
You then need to compile the following Kotlin program, linking against opengl2.klib, and run the resulting .kexe file to view the rotating triangle.
<
import kotlinx.cinterop.*
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setShader()
glutMainLoop()
}</
=={{header|Ol}}==
<
#!/usr/bin/ol
(import (lib gl2))
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(glVertex2f -0.0 +0.7)
(glEnd)))
</syntaxhighlight>
=={{header|Phix}}==
{{trans|
{{libheader|Phix/pGUI}}
{{libheader|Phix/online}}
You can run this online [http://phix.x10.mx/p2js/OpenGLShader.htm here].
<!--<
<span style="color: #000080;font-style:italic;">--
-- demo\rosetta\OpenGLShader.exw
-- =============================
--
-- Works identically to the rc JavaScript entry under pwa/p2js, but on desktop/Phix
-- the colours cycle round white/blue/orange once per second. Beyond my ken anyway.
--</span>
<span style="color: #008080;">with</span> <span style="color: #008080;">javascript_semantics</span>
<span style="color: #7060A8;">requires</span><span style="color: #0000FF;">(</span><span style="color: #008000;">"1.0.1"</span><span style="color: #0000FF;">)</span>
<span style="color: #008080;">include</span> <span style="color: #000000;">pGUI</span><span style="color: #0000FF;">.</span><span style="color: #000000;">e</span>
<span style="color: #008080;">include</span>
<span style="color: #004080;">Ihandln</span> <span style="color: #000000;">dlg</span>
<span style="color: #004080;">Ihandle</span> <span style="color: #000000;">canvas</span>
<span style="color: #008080;">function</span> <span style="color: #000000;">resize_cb</span><span style="color: #0000FF;">(</span><span style="color: #004080;">Ihandle</span> <span style="color: #000080;font-style:italic;">/*ih*/</span><span style="color: #0000FF;">,</span> <span style="color: #004080;">integer</span> <span style="color: #000000;">width</span><span style="color: #0000FF;">,
<span style="color: #7060A8;">glViewport</span><span style="color: #0000FF;">(</span><span style="color: #000000;">0</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">0</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">width</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">height</span><span style="color: #0000FF;">)</span>
<span style="color: #008080;">return</span> <span style="color: #004600;">IUP_DEFAULT</span>
<span style="color: #008080;">end</span> <span style="color: #008080;">function</span>
<span style="color: #008080;">
precision highp float;
uniform float u_time;
void main(void) {
// some gobbledegook
vec3 foo = vec3(pow(gl_FragCoord.xy, vec2(1.0 + sin(dot(vec4(1.0, 100.0, 0.0, 0.0), gl_FragCoord)))), 0.0);
foo *= mat3(1.2, 3.9, 1.4, 4.1, 0.2, 1.4, 2.5, 1.6, 7.2);
gl_FragColor = vec4(mod(foo + vec3(u_time), 1.0), 1.0);
}
"""</span>
<span style="color:
attribute vec3 a_position;
attribute vec4 a_color;
varying vec4 v_color;
void main(void) {
gl_Position = vec4(a_position, 1.0);
v_color = a_color;
}
"""</span>
<span style="color: #008080;">constant</span> <span style="color: #000000;">vertices</span> <span style="color: #0000FF;">=</span> <span style="color: #0000FF;">{</span>
<span style="color: #0000FF;">-</span><span style="color: #000000;">0.5</span><span style="color: #0000FF;">,</span> <span style="color: #0000FF;">-</span><span style="color: #000000;">0.5</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">0</span><span style="color: #0000FF;">,</span>
<span style="color: #0000FF;">+</span><span style="color: #000000;">0.5</span><span style="color: #0000FF;">,</span> <span style="color: #0000FF;">-</span><span style="color: #000000;">0.5</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">0</span><span style="color: #0000FF;">,</span>
<span style="color: #0000FF;">-</span><span style="color: #000000;">0.5</span><span style="color: #0000FF;">,</span> <span style="color: #0000FF;">+</span><span style="color: #000000;">0.5</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">0</span>
<span style="color: #0000FF;">}</span>
<span style="color: #008080;">function</span> <span style="color: #000000;">getShader</span><span style="color: #0000FF;">(</span><span style="color: #004080;">string</span> <span style="color: #000000;">src</span><span style="color: #0000FF;">,</span> <span style="color: #004080;">integer</span> <span style="color: #000000;">shader_type</span><span style="color: #0000FF;">)</span>
<span style="color: #004080;">integer</span> <span style="color: #000000;">shader</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">glCreateShader</span><span style="color: #0000FF;">(</span><span style="color: #000000;">shader_type</span><span style="color: #0000FF;">)</span>
<span style="color: #000080;font-style:italic;">// Compile shader from source</span>
<span style="color: #7060A8;">glShaderSource</span><span style="color: #0000FF;">(</span><span style="color: #000000;">shader</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">src</span><span style="color: #0000FF;">)</span>
<span style="color: #7060A8;">glCompileShader</span><span style="color: #0000FF;">(</span><span style="color: #000000;">shader</span><span style="color: #0000FF;">)</span>
<span style="color: #008080;">if</span> <span style="color: #008080;">not</span> <span style="color: #7060A8;">glGetShaderParameter</span><span style="color: #0000FF;">(</span><span style="color: #000000;">shader</span><span style="color: #0000FF;">,</span> <span style="color: #004600;">GL_COMPILE_STATUS</span><span style="color: #0000FF;">)</span> <span style="color: #008080;">then</span>
<span style="color: #7060A8;">crash</span><span style="color: #0000FF;">(</span><span style="color: #7060A8;">glGetShaderInfoLog</span><span style="color: #0000FF;">(</span><span style="color: #000000;">shader</span><span style="color: #0000FF;">))</span>
<span style="color: #008080;">end</span> <span style="color: #008080;">if</span>
<span style="color: #008080;">return</span> <span style="color: #000000;">shader</span>
<span style="color: #008080;">end</span> <span style="color: #008080;">function</span>
<span style="color: #
<span style="color: #008080;">procedure</span> <span style="color: #000000;">set_shader</span><span style="color: #0000FF;">()</span>
<span style="color: #7060A8;">IupGLMakeCurrent</span><span style="color: #0000FF;">(</span><span style="color: #000000;">canvas</span><span style="color: #0000FF;">)</span>
<span style="color: #004080;">integer</span> <span style="color: #000000;">
<span style="color: #7060A8;">glAttachShader</span><span style="color: #0000FF;">(</span><span style="color: #000000;">prog</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">
<span style="color: #
<span style="color: #
<span style="color: #
<span style="color: #
<span style="color: #
<span style="color: #
<span style="color: #
<span style="color: #004080;">integer</span> <span style="color: #000000;">
<span style="color: #000080;font-style:italic;">// And specify that we will be actually delivering data to those attributes.</span>
<span style="color: #7060A8;">glEnableVertexAttribArray</span><span style="color: #0000FF;">(</span><span style="color: #000000;">positionAttr</span><span style="color: #0000FF;">)</span>
<span style="color: #000000;">timeUniform</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">glGetUniformLocation</span><span style="color: #0000FF;">(</span><span style="color: #000000;">prog</span><span style="color: #0000FF;">,</span> <span style="color: #008000;">"u_time"</span><span style="color: #0000FF;">)</span>
<span style="color: #000080;font-style:italic;">// Store vertex positions and colors in array buffer objects.</span>
<span style="color: #004080;">integer</span> <span style="color: #000000;">positionBuffer</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">glCreateBuffer</span><span style="color: #0000FF;">()</span>
<span style="color: #7060A8;">glBindBuffer</span><span style="color: #0000FF;">(</span><span style="color: #004600;">GL_ARRAY_BUFFER</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">positionBuffer</span><span style="color: #0000FF;">)</span>
<span style="color: #0000FF;">{</span><span style="color: #004080;">integer</span> <span style="color: #000000;">size</span><span style="color: #0000FF;">,</span> <span style="color: #004080;">atom</span> <span style="color: #000000;">pData</span><span style="color: #0000FF;">}</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">glFloat32Array</span><span style="color: #0000FF;">(</span><span style="color: #000000;">vertices</span><span style="color: #0000FF;">)</span>
<span style="color: #7060A8;">glBufferData</span><span style="color: #0000FF;">(</span><span style="color: #004600;">GL_ARRAY_BUFFER</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">size</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">pData</span><span style="color: #0000FF;">,</span> <span style="color: #004600;">GL_STATIC_DRAW</span><span style="color: #0000FF;">)</span>
<span style="color: #7060A8;">glEnable</span><span style="color: #0000FF;">(</span><span style="color: #004600;">GL_DEPTH_TEST</span><span style="color: #0000FF;">);</span>
<span style="color: #000080;font-style:italic;">//Specify the array data to render. </span>
<span style="color: #7060A8;">glBindBuffer</span><span style="color: #0000FF;">(</span><span style="color: #004600;">GL_ARRAY_BUFFER</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">positionBuffer</span><span style="color: #0000FF;">)</span>
<span style="color: #7060A8;">glVertexAttribPointer</span><span style="color: #0000FF;">(</span><span style="color: #000000;">positionAttr</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">3</span><span style="color: #0000FF;">,</span> <span style="color: #004600;">GL_FLOAT</span><span style="color: #0000FF;">,</span> <span style="color: #004600;">false</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">0</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">0</span><span style="color: #0000FF;">)</span>
<span style="color: #008080;">end</span> <span style="color: #008080;">procedure</span>
<span style="color: #004080;">atom</span> <span style="color: #000000;">t0</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">time</span><span style="color: #0000FF;">()</span>
<span style="color: #008080;">function</span> <span style="color: #000000;">timer_cb</span><span style="color: #0000FF;">(</span><span style="color: #004080;">Ihandle</span> <span style="color: #000080;font-style:italic;">/*ih*/</span><span style="color: #0000FF;">)</span>
<span style="color: #7060A8;">glClearColor</span><span style="color: #0000FF;">(</span><span style="color: #000000;">0.3</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">0.3</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">0.3</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">1.0</span><span style="color: #0000FF;">)</span>
<span style="color: #004080;">integer</span> <span style="color: #0000FF;">{</span><span style="color: #000000;">w</span><span style="color: #0000FF;">,</span><span style="color: #000000;">h</span><span style="color: #0000FF;">}</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">IupGetIntInt</span><span style="color: #0000FF;">(</span><span style="color: #000000;">canvas</span><span style="color: #0000FF;">,</span><span style="color: #008000;">"DRAWSIZE"</span><span style="color: #0000FF;">)</span>
<span style="color: #7060A8;">glViewport</span><span style="color: #0000FF;">(</span><span style="color: #000000;">0</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">0</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">w</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">h</span><span style="color: #0000FF;">)</span>
<span style="color: #7060A8;">glUniform1f</span><span style="color: #0000FF;">(</span><span style="color: #000000;">timeUniform</span><span style="color: #0000FF;">,</span> <span style="color: #0000FF;">(</span><span style="color: #7060A8;">time</span><span style="color: #0000FF;">()-</span><span style="color: #000000;">t0</span><span style="color: #0000FF;">))</span>
<span style="color: #7060A8;">glClear</span><span style="color: #0000FF;">(</span><span style="color: #004600;">GL_COLOR_BUFFER_BIT</span> <span style="color: #0000FF;">||</span> <span style="color: #004600;">GL_DEPTH_BUFFER_BIT</span><span style="color: #0000FF;">)</span>
<span style="color: #004080;">integer</span> <span style="color: #000000;">numVertices</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">length</span><span style="color: #0000FF;">(</span><span style="color: #000000;">vertices</span><span style="color: #0000FF;">)/</span><span style="color: #000000;">3</span><span style="color: #0000FF;">;</span> <span style="color: #000080;font-style:italic;">// 3 coordinates per vertex</span>
<span style="color: #7060A8;">glDrawArrays</span><span style="color: #0000FF;">(</span><span style="color: #004600;">GL_TRIANGLES</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">0</span><span style="color: #0000FF;">,</span> <span style="color: #000000;">numVertices</span><span style="color: #0000FF;">);</span>
<span style="color: #7060A8;">glFlush</span><span style="color: #0000FF;">()</span>
<span style="color: #008080;">return</span> <span style="color: #004600;">IUP_DEFAULT</span>
<span style="color: #008080;">end</span> <span style="color: #008080;">function</span>
<span style="color: #008080;">procedure</span> <span style="color: #000000;">main</span><span style="color: #0000FF;">()</span>
Line 551 ⟶ 602:
<span style="color: #000000;">canvas</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">IupGLCanvas</span><span style="color: #0000FF;">(</span><span style="color: #008000;">"RESIZE_CB"</span><span style="color: #0000FF;">,</span> <span style="color: #7060A8;">Icallback</span><span style="color: #0000FF;">(</span><span style="color: #008000;">"resize_cb"</span><span style="color: #0000FF;">),</span> <span style="color: #008000;">"RASTERSIZE=640x480"</span><span style="color: #0000FF;">)</span>
<span style="color: #000000;">dlg</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">IupDialog</span><span style="color: #0000FF;">(</span><span style="color: #000000;">canvas</span><span style="color: #0000FF;">,</span> <span style="color: #008000;">"TITLE=OpenGLShader, SHRINK=YES"</span><span style="color: #0000FF;">)</span>
<span style="color: #7060A8;">
<span style="color: #000000;">set_shader</span><span style="color: #0000FF;">()</span>
<span style="color: #7060A8;">
<span style="color: #004080;">Ihandle</span> <span style="color: #000000;">timer</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">IupTimer</span><span style="color: #0000FF;">(</span><span style="color: #7060A8;">Icallback</span><span style="color: #0000FF;">(</span><span style="color: #008000;">"timer_cb"</span><span style="color: #0000FF;">),</span> <span style="color: #000000;">1000</span><span style="color: #0000FF;">/</span><span style="color: #000000;">20</span><span style="color: #0000FF;">)</span>
<span style="color: #
<span style="color: #7060A8;">
<span style="color: #000000;">dlg</span> <span style="color: #0000FF;">=</span> <span style="color: #7060A8;">IupDestroy</span><span style="color: #0000FF;">(</span><span style="color: #000000;">dlg</span><span style="color: #0000FF;">)</span>
<span style="color: #7060A8;">IupClose</span><span style="color: #0000FF;">()</span>
<span style="color: #008080;">end</span> <span style="color: #008080;">if</span>
<span style="color: #008080;">end</span> <span style="color: #008080;">procedure</span>
<span style="color: #000000;">main</span><span style="color: #0000FF;">()</span>
<!--</
=={{header|Racket}}==
<
(require typed/opengl)
Line 638 ⟶ 692:
(define gl (new my-canvas% [parent win]))
(send win show #t)</
=={{header|Tcl}}==
Line 646 ⟶ 700:
Using the [http://www.tcl3d.org Tcl3d] library and liberally borrowing from [http://wiki.tcl.tk/41477 this pixel shader demo on the wiki], here is a brute translation of the C implementation.
<syntaxhighlight lang="tcl">
package require tcl3d
Line 709 ⟶ 763:
set_shader
render
</syntaxhighlight>
=={{header|Wren}}==
Line 717 ⟶ 771:
<br>
As it's not currently possible for Wren-cli to access OpenGL directly, we embed a Wren script in a C application to complete this task. See the [[OpenGL#Wren]] task for some of the issues involved here.
<
import "random" for Random
Line 851 ⟶ 905:
}
setShader.call()
Glut.setOption(GLUT_ACTION_ON_WINDOW_CLOSE, GLUT_ACTION_GLUTMAINLOOP_RETURNS)</
<br>
We now embed this Wren script in the following C program, compile and run it.
<
#include <stdio.h>
#include <string.h>
Line 1,103 ⟶ 1,157:
vm = wrenNewVM(&config);
const char* module = "main";
const char* fileName = "
char *script = readFile(fileName);
WrenInterpretResult result = wrenInterpret(vm, module, script);
Line 1,120 ⟶ 1,174:
free(script);
return 0;
}</
{{out}}
|