78 lines
2.4 KiB
Nim
78 lines
2.4 KiB
Nim
## This example show how to have real time pixie using glut API.
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import math, opengl, opengl/glu, opengl/glut, pixie
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let
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w: int32 = 256
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h: int32 = 256
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var
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screen = newImage(w, h)
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ctx = newContext(screen)
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frameCount = 0
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proc display() {.cdecl.} =
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## Called every frame by GLUT
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# draw shiny sphere on gradient background
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let linerGradient = newPaint(pkGradientLinear)
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linerGradient.gradientHandlePositions.add(vec2(0, 0))
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linerGradient.gradientHandlePositions.add(vec2(0, 256))
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linerGradient.gradientStops.add(
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ColorStop(color: color(0, 0, 0, 1), position: 0))
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linerGradient.gradientStops.add(
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ColorStop(color: color(1, 1, 1, 1), position: 1))
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ctx.fillStyle = linerGradient
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ctx.fillRect(0, 0, 256, 256)
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let radialGradient = newPaint(pkGradientRadial)
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radialGradient.gradientHandlePositions.add(vec2(128, 128))
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radialGradient.gradientHandlePositions.add(vec2(256, 128))
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radialGradient.gradientHandlePositions.add(vec2(128, 256))
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radialGradient.gradientStops.add(
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ColorStop(color: color(1, 1, 1, 1), position: 0))
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radialGradient.gradientStops.add(
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ColorStop(color: color(0, 0, 0, 1), position: 1))
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ctx.fillStyle = radialGradient
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ctx.fillCircle(circle(
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vec2(128.0, 128.0 + sin(float32(frameCount)/10.0) * 20),
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76.8
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))
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# update texture with new pixels from surface
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var dataPtr = ctx.image.data[0].addr
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glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, GLsizei w, GLsizei h, GL_RGBA,
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GL_UNSIGNED_BYTE, dataPtr)
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# draw a quad over the whole screen
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glClear(GL_COLOR_BUFFER_BIT)
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glBegin(GL_QUADS)
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glTexCoord2d(0.0, 0.0); glVertex2d(-1.0, +1.0)
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glTexCoord2d(1.0, 0.0); glVertex2d(+1.0, +1.0)
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glTexCoord2d(1.0, 1.0); glVertex2d(+1.0, -1.0)
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glTexCoord2d(0.0, 1.0); glVertex2d(-1.0, -1.0)
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glEnd()
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glutSwapBuffers()
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inc frameCount
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glutPostRedisplay() # ask glut to draw next frame
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glutInit()
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glutInitDisplayMode(GLUT_DOUBLE)
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glutInitWindowSize(w, h)
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discard glutCreateWindow("GLUT/Pixie")
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glutDisplayFunc(display)
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loadExtensions()
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# allocate a texture and bind it
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var dataPtr = ctx.image.data[0].addr
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glTexImage2D(GL_TEXTURE_2D, 0, 3, GLsizei w, GLsizei h, 0, GL_RGBA,
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GL_UNSIGNED_BYTE, dataPtr)
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glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST)
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glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST)
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glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP)
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glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP)
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glEnable(GL_TEXTURE_2D)
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glutMainLoop()
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