我想从HLSL中的高度图创建法线图。我跟着这个用于GLSL的https://stackoverflow.com/a/5284527/451136。这是我如何翻译GLSL到HLSL:
GLSL:来自高度图的法线图
uniform sampler2D unit_wave
noperspective in vec2 tex_coord;
const vec2 size = vec2(2.0,0.0);
const ivec3 off = ivec3(-1,0,1);
vec4 wave = texture(unit_wave, tex_coord);
float s11 = wave.x;
float s01 = textureOffset(unit_wave, tex_coord, off.xy).x;
float s21 = textureOffset(unit_wave, tex_coord, off.zy).x;
float s10 = textureOffset(unit_wave, tex_coord, off.yx).x;
float s12 = textureOffset(unit_wave, tex_coord, off.yz).x;
vec3 va = normalize(vec3(size.xy,s21-s01));
vec3 vb = normalize(vec3(size.yx,s12-s10));
vec4 bump = vec4(cross(va,vb), s11);
HLSL:
sampler2D image : register(s0);
noperspective float2 TEXCOORD;
static const float2 size = (2.0,0.0);
static const int3 off = (-1,0,1);
float4 main(float2 uv : TEXCOORD) : COLOR
{
float4 color = tex2D(image, uv);
float s11 = color.x;
float s01 = tex2D(image, uv + off.xy).x;
float s21 = tex2D(image, uv + off.zy).x;
float s10 = tex2D(image, uv + off.yx).x;
float s12 = tex2D(image, uv + off.yz).x;
float3 va = normalize((size.xy,s21-s01));
float3 vb = normalize((size.yx,s12-s10));
float4 bump = (cross(va,vb), s11);
return bump;
}
输出是黑白图像,与较暗的像素是更透明的(因为alpha是高度)。
如何从高度图中生成像这样的普通地图http://www.filterforge.com/filters/3051-normal.jpg?
编辑
我跟着megadan的建议,我也有,我修正了一些synthax错误。这里是工作的HLSL代码:
float Width : register(C0);
float Height : register(C1);
sampler2D image : register(s0);
noperspective float2 TEXCOORD;
static const float2 size = {2.0,0.0};
static const float3 off = {-1.0,0.0,1.0};
static const float2 nTex = {Width, Height};
float4 main(float2 uv : TEXCOORD) : COLOR
{
float4 color = tex2D(image, uv.xy);
float2 offxy = {off.x/nTex.x , off.y/nTex.y};
float2 offzy = {off.z/nTex.x , off.y/nTex.y};
float2 offyx = {off.y/nTex.x , off.x/nTex.y};
float2 offyz = {off.y/nTex.x , off.z/nTex.y};
float s11 = color.x;
float s01 = tex2D(image, uv.xy + offxy).x;
float s21 = tex2D(image, uv.xy + offzy).x;
float s10 = tex2D(image, uv.xy + offyx).x;
float s12 = tex2D(image, uv.xy + offyz).x;
float3 va = {size.x, size.y, s21-s01};
float3 vb = {size.y, size.x, s12-s10};
va = normalize(va);
vb = normalize(vb);
float4 bump = {(cross(va,vb))/2 + 0.5, 1.0};
return bump;
}
,我读了使用GetDimensions自动获取宽度和纹理的高度支持的Direct3D 10.1或更高,所以纹理的宽度和高度必须传递到因为我需要它与Direct3D 9兼容。
嗯,即时通讯仍然没有得到任何颜色。事实上即时获得相同的结果。我之前也必须犯错。 – Infodayne 2014-09-25 20:42:51
再看看它,我认为你的纹理坐标有问题。 uv应该在[0,1]的范围内。当你添加它时,它会将它放在范围之外,结果取决于任何纹理寻址模式处于活动状态。在每个tex2D样本中,都需要将第一个组件的纹理宽度除以第二个组件的纹理高度。另外,交叉积的结果的值在[-1,1]范围内。您需要将这些转换为[0,1]以获得颜色。所以交叉(vb,va)* 0.5 + 0.5 – megadan 2014-09-25 22:45:49
太棒了,那就是诀窍。我确实必须将交叉产品保留为交叉(va,vb)。谢谢。 – Infodayne 2014-09-26 02:11:11