source-engine/materialsystem/stdshaders/particlesphere_vs11.fxc

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2020-04-22 16:56:21 +00:00
// DYNAMIC: "FOGTYPE" "0..1"
#include "common_vs_fxc.h"
static const int g_FogType = FOGTYPE;
const float4 cCustomConstants[6] : register( SHADER_SPECIFIC_CONST_0 );
const float4 g_vLightPosition : register( SHADER_SPECIFIC_CONST_0 );
const float4 g_vLightColor : register( SHADER_SPECIFIC_CONST_1 ); // range 0-1
const float g_flLightIntensity : register( SHADER_SPECIFIC_CONST_2 ); // scales g_vLightColor
struct VS_INPUT
{
// If this is float4, and the input is float3, the w component default to one.
float4 vPos : POSITION;
float2 vBumpTexCoord : TEXCOORD0;
float4 vAmbientColor : COLOR0;
};
struct VS_OUTPUT
{
float4 projPos : POSITION;
#if !defined( _X360 )
float fog : FOG;
#endif
float2 vBumpTexCoord : TEXCOORD0;
float3 vTangentSpaceLightDir : TEXCOORD1;
float3 vAmbientColor : TEXCOORD2;
float4 vDirLightScale : COLOR0;
};
VS_OUTPUT main( const VS_INPUT v )
{
VS_OUTPUT o;
// Transform the input position.
float4 projPos = mul( v.vPos, cModelViewProj );
o.projPos = projPos;
#if !defined( _X360 )
// Setup fog.
o.fog = CalcFog( mul( v.vPos, cModel[0] ), projPos, g_FogType );
#endif
// Copy texcoords over.
o.vBumpTexCoord = v.vBumpTexCoord;
// Copy the vertex color over.
o.vAmbientColor = v.vAmbientColor;
// ------------------------------------------------------------------------------
// Generate a tangent space and rotate L.
// This can be thought of as rotating the normal map to face the viewer.
//
// This is useful when a particle is way off to the side of the screen.
// You should be looking at the half-sphere with a normal pointing from the
// particle to the viewer. Instead, you're looking at the half-sphere with
// a normal along Z. This tangent space builder code fixes the problem.
//
// Note that since the model and view matrices are identity, the coordinate
// system has X=right, Y=up, and Z=behind you (negative Z goes into the screen).
// ------------------------------------------------------------------------------
// This basis wants Z positive going into the screen so flip it here.
float4 vForward = normalize( float4( v.vPos.x, v.vPos.y, -v.vPos.z, 1 ) );
// This is the same as CrossProduct( vForward, Vector( 1, 0, 0 ) )
float4 vUp = normalize( float4( 0, vForward.z, -vForward.y, vForward.w ) );
// vRight = CrossProduct( vUp, vForward )
float4 vRight = vUp.yzxw * vForward.zxyw;
vRight += -vUp.zxyw * vForward.yzxw;
// Put the light in tangent space.
float4 vToLight = g_vLightPosition - v.vPos;
float4 vTangentSpaceLight = vRight*vToLight.x + vUp*vToLight.y + vForward*vToLight.z;
// Output texcoord 1 holds the normalized transformed light direction.
o.vTangentSpaceLightDir = normalize( vTangentSpaceLight ) * 0.5 + 0.5; // make it 0-1 for the pixel shader
// Handle oversaturation here. The shader code already scaled the light color so its max value is 1,
// so if our intensity/distance scale is > 1, then all we need to do is use the light color.
float flTransposedLenSqr = dot( vTangentSpaceLight, vTangentSpaceLight );
float flScaledIntensity = g_flLightIntensity / flTransposedLenSqr;
if ( flScaledIntensity > 1 )
{
o.vDirLightScale.xyz = g_vLightColor;
}
else
{
o.vDirLightScale.xyz = g_vLightColor * flScaledIntensity;
}
// Alpha comes right from the vertex color.
o.vDirLightScale.a = v.vAmbientColor.a;
return o;
}