164 lines
5.5 KiB
GLSL
164 lines
5.5 KiB
GLSL
vs.1.1
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# DYNAMIC: "DOWATERFOG" "0..1"
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#include "macros.vsh"
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$cQuarter = "c91.x";
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;------------------------------------------------------------------------------
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; Constants specified by the app
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; c0 = (0, 1, 2, 0.5)
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; c1 = (1/2.2, 0, 0, 0)
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; 2 = camera position *in world space*
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; c4-c7 = modelViewProj matrix (transpose)
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; c8-c11 = ViewProj matrix (transpose)
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; c12-c15 = model->world matrix (transpose)
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; c16 = [fogStart, fogEnd, fogRange, undefined]
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; c17-c20 = model->view matrix (transpose)
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;
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; The ParticleSphere lighting equation is:
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; A + [N dot ||L - P||] * C * r / |L - P|^2
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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 = directional 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 just does the |L - P| part and the pixel shader does the rest.
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;
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; Vertex components
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; $vPos = Position
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; $vSpecular = Directional light color
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; $vColor = Ambient color (and alpha)
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; $vTexCoord0 = Texture coordinates for normal map
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; $vTexCoord0.z = Index into the light list for light info
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;------------------------------------------------------------------------------
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; Constant registers
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;------------------------------------------------------------------------------
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;------------------------------------------------------------------------------
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; Vertex blending
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;------------------------------------------------------------------------------
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&AllocateRegister( \$projPos );
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; Transform position from object to projection space
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dp4 $projPos.x, $vPos, $cModelViewProj0
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dp4 $projPos.y, $vPos, $cModelViewProj1
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dp4 $projPos.z, $vPos, $cModelViewProj2
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dp4 $projPos.w, $vPos, $cModelViewProj3
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mov oPos, $projPos
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;------------------------------------------------------------------------------
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; Fog
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;------------------------------------------------------------------------------
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alloc $worldPos
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if( $DOWATERFOG == 1 )
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{
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; Get the worldpos z component only since that's all we need for height fog
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dp4 $worldPos.z, $vPos, $cModel2
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}
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&CalcFog( $worldPos, $projPos );
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free $worldPos
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&FreeRegister( \$projPos );
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;------------------------------------------------------------------------------
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; Setup to index our directional light.
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;------------------------------------------------------------------------------
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mov a0.x, $vTexCoord0.z
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;------------------------------------------------------------------------------
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; Copy texcoords for the normal map texture
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;------------------------------------------------------------------------------
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mov oT0, $vTexCoord0
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mov oT2.xyz, $vColor
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; FIXME : the rest of this needs to use AllocateRegister
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;------------------------------------------------------------------------------
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; Generate a tangent space and rotate L.
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; This can be thought of as rotating the normal map to face the viewer.
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;
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; This is useful when a particle is way off to the side of the screen.
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; You should be looking at the half-sphere with a normal pointing from the
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; particle to the viewer. Instead, you're looking at the half-sphere with
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; a normal along Z. This tangent space builder code fixes the problem.
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;
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; Note that since the model and view matrices are identity, the coordinate
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; system has X=right, Y=up, and Z=behind you (negative Z goes into the screen).
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;------------------------------------------------------------------------------
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; r5 (forward) = normalized P
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dp3 r1, $vPos, $vPos
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rsq r5, r1
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mul r5, r5, $vPos
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mov r5.z, -r5.z ; This basis wants Z positive going into the screen
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; so flip it here.
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; r1 (up) = r5 x c24
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mul r1, r5.xzyw, $SHADER_SPECIFIC_CONST_0; (This effectively does a cross product with [1,0,0,0]
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; You wind up with [0, r5.z, -r5.y, 1]
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dp3 r2, r1, r1
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rsq r2, r2
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mul r1, r1, r2
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; r2 (right) = r1 x r5
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mul r2, r1.yzxw, r5.zxyw
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mad r2, -r1.zxyw, r5.yzxw, r2
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sub r3, c[45 + a0.x], $vPos ; r3 = L - P
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; transposed matrix mul
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mul r0, r2, r3.xxxx ; x * right
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mad r0, r1, r3.yyyy, r0 ; + y * up
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mad r0, r5, r3.zzzz, r0 ; + z * forward
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;------------------------------------------------------------------------------
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; Put ||L - P|| into t1
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;------------------------------------------------------------------------------
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dp3 r2, r0, r0 ; r2 = Length(L - P)^2
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rsq r3, r2 ; r3 = 1 / Length(L - P)
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mul r8, r0, r3 ; r8 = Normalize(L - P)
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mul r9, r8, $cQuarter ; r9 = Normalize(L - P) * 0.25
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add oT1, r9, c0.w ; oT1 = Normalize(L - P) * 0.25 + 0.5
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;------------------------------------------------------------------------------
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; Setup the diffuse light color (C * r / ||L - P||^2)
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;------------------------------------------------------------------------------
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mul r8, c[46 + a0.x], $vSpecular ; r8 = C * r
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rcp r7, r2 ; r7 = 1 / Length(L - P)^2
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; rescale the color if necessary
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mul r8, r8, r7 ; r8 = C * r / Length(L - P)^2
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; We're doing both parts of an if statement here, with each part scaled by 0 or 1.
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mul r9, r7, c[46 + a0.x] ; r9 = r / Length(L - P)^2
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; If the light intensity scales the color > 1
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sge r10, r9.xxxx, $cOne ; r10.x = 1 if the color's max component > 1
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rcp r6, r9.xxxx
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mul r6, r6, r10.xxxx ; r6 = 1 / max_component or [0,0,0,0] if max_component < 1
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mul r2, r8, r6 ; rescaled color (all zeros if no component was > 1)
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; else
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slt r11, r9.xxxx, $cOne ; r11.x = 1 if the color's max component < 1
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mad oD0.xyz, r8, r11, r2 ; if it was rescaled, then r8*r11 = 0
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; if not, then r8*r11 = the original color
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mov oD0.a, $vColor.a ; Pass in vertex alpha so the pixel shader can use it.
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