40 lines
1.2 KiB
Plaintext
40 lines
1.2 KiB
Plaintext
ps.1.1
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;------------------------------------------------------------------------------
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; Sphere-lit particle pixel shader.
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;
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; The ParticleSphere lighting equation is:
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; A + [[N dot |L - P|] * 0.5 + 0.5] * C * r / ||L - P||
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;
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; where:
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; A = ambient light color
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; N = particle normal (stored in the texture)
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; L = light position
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; P = point on surface
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; C = directional light color
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; r = directional light intensity
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;
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; This shader takes as input:
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; t0 = Normal map texture coordinates (N)
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; t1 = Light vector Normalize(L - P) * 0.5 in range [0,1]
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; v0 = Directional color (C * r / ||L - P||^2) * 0.5
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; t2 = Ambient light color (A)
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; c0 = 0.5
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;
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; and outputs [v1 + (sample(t0) dot t1) * 0.5f + 0.5f]
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;------------------------------------------------------------------------------
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tex t0 ; Get the 3-vector from the normal map
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texcoord t1 ; Interpret tcoord t1 as color data.
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texcoord t2 ; Ambient light color
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dp3 r1, t0_bx2, t1_bx2 ; r0 = sample(t0) dot t1
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add r0, r1, c0 ; + 0.5
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mul r1, v0, r0 ; scale the dot product by the dirlight's actual color
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add r0.rgb, r1, t2 ; add the ambient color in v1
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mul r0.a, t0, v0 ; Alpha = normal map alpha * vertex alpha
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