pixel_shader.html
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<html>
<head>
<title>Bitmap Font Generator - Documentation</title>
</head>
<body>
<h1>Bitmap Font Generator - Documentation</h1>
<p><a href="../documentation.html">Back to main page</a></p>
<h2>Pixel shader example</h2>
<p>This pixel shader shows how to decode the color from a font texture with characters packed
into all 4 channels, and each channel using special encoding to store the character with the
outline. The texture is also allowed to store full 32bit images for some characters.</p>
<pre>
// DirectX 9 pixel shader
float4 PixScene( float4 color : COLOR0,
int4 chnl : TEXCOORD1,
float2 tex0 : TEXCOORD0 ) : COLOR0
{
float4 pixel = tex2D(g_samScene, tex0);
if( dot(vector(1,1,1,1), chnl) )
{
float val = dot(pixel, chnl);
pixel.rgb = val > 0.5 ? 2*val-1 : 0;
pixel.a = val > 0.5 ? 1 : 2*val;
}
return pixel * color;
}
</pre>
<p>The chnl texture coordinate is a 4D vector that shows which channel the character should be read
from. If this is (0,0,0,0) the character is interpreted as a 32 bit image. The texture coordinate
can be stored in a UBYTE4 type, so it doesn't require much bandwidth when being sent to the video card.</p>
</body>
</html>