Hello,

(test project at the bottom of the post)

I am trying to write a shader with some environment mapping, but i can't seem to access mipmaps of skycube in the shader.

I simplified it to this:

This is basically envBump shader from the built-in shader library with minimal modifications(listed below the shader):

Code:
#include <transform>
#include <fog>
#include <pos>
#include <normal>
#include <light>
#include <vecskill>
#include <color>

float vecSunColor;
float fAlbedo;

texture entSkin1;	// texture
texture entSkin2;	// normal map
texture mtlSkin1;

sampler sBaseTex = sampler_state { Texture = <entSkin1>; MipFilter = Linear;	};
sampler sBump = sampler_state { Texture = <entSkin2>; MipFilter = None;	};
sampler sEnviro = sampler_state { Texture = <mtlSkin1>; MipFilter = Linear; MagFilter = Linear; MinFilter = Linear;	};

struct bumpOut
{
	float4 Pos:    	POSITION;
	float  Fog:			FOG;
	float4 Ambient:	COLOR0;
	float2 Tex:   		TEXCOORD0;
	float3 PosWorld: 	TEXCOORD1;	
	float3 Vecskill:  TEXCOORD2;
	float3 Normal: 	TEXCOORD3;	
};

bumpOut perPixel_VS(
in float4 inPos: 		POSITION, 
in float3 inNormal:	NORMAL,
in float2 inTex: 		TEXCOORD0,
in float3 inTangent: TEXCOORD2)
{
	bumpOut Out;

	Out.Pos	= DoTransform(inPos);
	Out.Tex	= inTex;
	Out.Fog	= DoFog(inPos);
	Out.Ambient = DoAmbient();	

	float facBump = DoDefault(vecSkill41.x*0.01,50*0.01);
	float facTex = DoDefault(vecSkill41.y*0.01,50*0.01);
	Out.Vecskill.x = facBump;
	Out.Vecskill.y = facTex;
	Out.Vecskill.z = vecSkill41.z;
	Out.PosWorld = DoPos(inNormal);
	Out.Normal = DoNormal(inNormal);
	
	return Out;		
}


float4 diffuseBump_PS(bumpOut In): COLOR
{
	float4 base = tex2D(sBaseTex,In.Tex);
	float3 bumpNormal = tex2D(sBump,In.Tex)*2-1;
	
	float facBump = In.Vecskill.x;
	float3 cubeTexCoord = normalize(reflect(In.PosWorld - vecViewPos,In.Normal));
	cubeTexCoord = cubeTexCoord + (bumpNormal - cubeTexCoord )*facBump;
	float4 newCubeTexCoord = float4(cubeTexCoord.x,cubeTexCoord.y,cubeTexCoord.z,In.Vecskill.z);
	float4 environment = texCUBElod(sEnviro,newCubeTexCoord)*(vecColor+vecSunColor*vecDiffuse)*base.w;	
	float facTex = In.Vecskill.y;
	float4 resultingBase = lerp(environment,base,facTex);
			
	return resultingBase * (0.5+In.Ambient);
}

technique bump
{
	pass One
	{		
		VertexShader = compile vs_3_0 perPixel_VS();
		PixelShader = compile ps_3_0 diffuseBump_PS();
	}
}

technique fallback { pass one { } }

Changes:
  • Added skill43 (vecSkill41.z) as miplevel
  • Changed texCUBE to texCUBElod and since texCUBElod expects mip level on w component of texCoord i added skill43 as w of newCubeTexCoord.
  • bumped versions up to 3_0 because texCUBElod


This is the lite-c code to test the material:
Code:
#include <acknex.h>
#include <default.c>
#include <mtlfx.c>

#define PRAGMA_POINTER

BMAP* bmap_skycube = "desertsky+6.tga";


MATERIAL* matTEST = {
	effect = "skymap.fx";
}

function materialInit()
{
	bmap_skycube = bmap_to_mipmap(bmap_skycube);
	bmap_to_cubemap(bmap_skycube); // <------ THIS LINE !!!!!
	matTEST->skin1 = bmap_skycube;
}

void main(){
	
	var facbump = 1;
	var factext = 1;
	var mipLevel = 1;
	
	d3d_anisotropy = 7;
	d3d_mipmapping = 4;	
	mip_levels = 10;
	level_load("");
	materialInit();
	ENTITY* box = ent_create("cube.mdl",nullvector,NULL);
	box->material = matTEST;
	
	box->skill41 = floatv(facbump);
	box->skill42 = floatv(factext);
	box->skill43 = floatv(mipLevel);
	
	camera->x = -31;
	camera->z = 20;
	camera->y = -4; 
	camera->pan = 16;
	camera->tilt = -32;
	
	video_set(800,600,0,0);
	
	while(!key_esc){
		DEBUG_VAR(mipLevel,50);
		if(key_5 || key_6){
			mipLevel += (key_5 - key_6)*time_step/6;
			box->skill43 = floatv(mipLevel);
		}
		wait(1);
	}
}


It creates a cube, applies the material, keys 5 and 6 modifies the mip level.

Expected result is that when i press 5 i get a more blurry environment map.

Actual result is that it does not change a thing which leds me to believe that the cubemap loses mipmaps when bmap_to_cubemap is called.


When i remove this line
Code:
bmap_to_cubemap(bmap_skycube);

from materialInit() function, i get the expected result:

(except it's not a cubemap anymore and everything is garbled)

Test project: Link (try commenting line 17 in cubemiptest.c)

3333333333