OpenGL pixel shader: Difference between revisions
→{{header|Racket}}: implementation added
(Tcl implementation added) |
(→{{header|Racket}}: implementation added) |
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</body>
</html></lang>
=={{header|Racket}}==
<lang racket>#lang racket/gui
(require typed/opengl)
(define (resize w h)
(glViewport 0 0 w h))
;; shaders gotten from [#C]
(define shader-source:fragment
#<<<
varying float x, y, z;
uniform float r_mod;
float rand(float s, float r) { return mod(mod(s, r + r_mod) * 112341, 1); }
void main() {
gl_FragColor = vec4(rand(gl_FragCoord.x, x),
rand(gl_FragCoord.y, y),
rand(gl_FragCoord.z, z),
1);
}
<
)
(define shader-source:vertex
#<<<
varying float x, y, z;
void main() {
gl_Position = ftransform();
x = gl_Position.x;
y = gl_Position.y;
z = gl_Position.z;
x += y;
y -= x;
z += x - y;
}
<
)
(define (draw-opengl prg)
(glClearColor 0.0 0.0 0.0 0.0)
(glClear GL_COLOR_BUFFER_BIT)
(glShadeModel GL_SMOOTH)
(glMatrixMode GL_PROJECTION)
(glLoadIdentity)
(glOrtho 0.0 1.0 0.0 1.0 -1.0 1.0)
(glMatrixMode GL_MODELVIEW)
(glLoadIdentity)
(glBegin GL_TRIANGLES)
(glVertex3d 0.25 0.25 0.0)
(glVertex3d 0.75 0.25 0.0)
(glVertex3d 0.75 0.75 0.0)
(glEnd))
(define my-canvas%
(class* canvas% ()
(inherit with-gl-context swap-gl-buffers)
(define the-program #f)
(define/override (on-paint)
(with-gl-context
(λ()
(unless the-program
(set! the-program
(create-program (load-shader (open-input-string shader-source:fragment)
GL_FRAGMENT_SHADER)
(load-shader (open-input-string shader-source:vertex)
GL_VERTEX_SHADER)))
(glUseProgram the-program))
(draw-opengl the-program) (swap-gl-buffers))))
(define/override (on-size width height)
(with-gl-context (λ() (resize width height))))
(super-instantiate () (style '(gl)))))
(define win (new frame% [label "Racket Rosetta Code OpenGL example"]
[min-width 200] [min-height 200]))
(define gl (new my-canvas% [parent win]))
(send win show #t)</lang>
=={{header|Tcl}}==
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