Hiya guys 'n gals.
I need some help with my below multi-tex shader, please.
As you can see from the code, I use the "MagFilter=NONE;" sampler state
to prevent the shader 'extrapolating' the texture co-ordinates when a pixel
is 'somewhere between' pixels in the blend map.
This give me nice SHARP edges based on my EXTREMELY low-resolution blend-map.
But, if I just use the usual "MagFilter=LINEAR;" or the like, then the
edges overlap TOO MUCH with neighbouring pixels.
But, I would LIKE to find a happy "medium" programmatically.
So, IF the texture co-ords were in 'whole numbers'... say 0->128
I could just truncate off a controlled portion of the decimal places with
the trusty old "integer()" function, BUT, as you know, the co-ordinate
system for textures is in the range 0.0->1.0, so I dont know where to begin...
Hopefully it can happen in the vertex-shader portion, as Im already short of
available calculation 'slots' in the pixel shader as is...
Im not looking for a "fix it for me" job here, because I want and need to
fully understand what Im doing, because this shader is a work-in-progress
as a proof-of-concept for something larger...
Thanks a heap guys...
//-----------------------------------------------------------------------------------------
//-----------------------------------------------------------------------------------------
//
float4 vecSkill1; // from material skills :: vecSkill1.x = texture-scaling multiplier
//
//-----------------------------------------------------------------------------------------
//-----------------------------------------------------------------------------------------
//
// Engine Variables
float4x4 matWorldViewProj, matWorld;
float4 vecFog, vecViewPos, vecSunColor, vecLight; float3 vecSunDir;
float4 vecLightPos[8], vecLightColor[8];
//
// Textures
Texture entSkin1;
Texture roof_shader_D_bmap;
Texture roof_shader_R_bmap;
Texture roof_shader_G_bmap;
Texture roof_shader_B_bmap;
//
// Samplers
sampler blendmap=sampler_state { Texture=<entSkin1>; MagFilter=NONE; };
sampler map_D = sampler_state { Texture=<roof_shader_D_bmap>; };
sampler map_R = sampler_state { Texture=<roof_shader_R_bmap>; };
sampler map_G = sampler_state { Texture=<roof_shader_G_bmap>; };
sampler map_B = sampler_state { Texture=<roof_shader_B_bmap>; };
//
//-----------------------------------------------------------------------------------------
//
// Vertex Shader
void multitex_VS(float4 Pos :POSITION, float4 Norm:NORMAL, float2 Tex:TEXCOORD0,
out float4 _Pos :POSITION, out float2 _Tex:TEXCOORD1,
out float2 _Norm:TEXCOORD2, out float3 _View:TEXCOORD3 )
{
// transform or direct-pipe vertex data
_Pos = mul(Pos, matWorldViewProj); _View = mul(Pos, matWorld);
_Tex=Tex * vecSkill1.x; _Norm=Norm;
}
//
//-----------------------------------------------------------------------------------------
//
// Per-Pixel Shader
float4 multitex_PS( float4 Pos :POSITION, float2 Tex :TEXCOORD1,
float2 Norm:TEXCOORD2, float3 View:TEXCOORD3 ): COLOR
{
// extract blending data
float4 BlendColor = tex2D(blendmap, Tex/vecSkill1.x);
// "blend" the textures together
float4 Color = tex2D(map_D, Tex);
Color = lerp(Color, tex2D(map_R, Tex), BlendColor.r);
Color = lerp(Color, tex2D(map_G, Tex), BlendColor.g);
Color = lerp(Color, tex2D(map_B, Tex), BlendColor.b);
//
// calculate the diffuse 'sunlight' levels
float4 Lights, Diffuse = (vecLight+saturate(dot(-vecSunDir, Norm))*vecSunColor);
//
// append the diffuse 'dynamic-light' levels
for(int i = 0; i < 3; i++) // need try to squeeze out 4 dynamic lights
{ Lights.xyz = vecLightPos[i]-View;
Lights.a = saturate(1.0f - length(Lights.xyz/vecLightPos[i].w));
Diffuse += saturate(dot(normalize(Lights.xyz), Norm))*vecLightColor[i]*Lights.a;
}
//
return float4((Color*Diffuse).rgb, BlendColor.a);
}
//
//-----------------------------------------------------------------------------------------
//
// Render Pass
technique multitex
{
pass one
{
VertexShader = compile vs_1_1 multitex_VS();
PixelShader = compile ps_1_1 multitex_PS();
}
}
//
//-----------------------------------------------------------------------------------------
//-----------------------------------------------------------------------------------------
