Tagged Questions

A proprietary shading language developed by Microsoft for use with the Microsoft Direct3D API.

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2
votes
1answer
315 views

Is this GLSL equivalent to this HLSL?

I was wondering if the both shader codes are equivalent. So the question is, is this GLSL vNormal = mat3(FUSEE_ITMV[0].xyz, FUSEE_ITMV[1].xyz, FUSEE_ITMV[2].xyz) * fuNormal; Equivalent to this ...
1
vote
1answer
159 views

Does HLSL implement Shader Model LOD instruction?

The DX Shader Model 5.0 has a lod instruction. It returns "the LOD (level of detail) that would be used for texture filtering". Does HLSL have a built-in intrinsic that can do the same? I know I ...
0
votes
0answers
30 views

Skip the first RenderTarget when writing to MRT with Opaque blending

I am writing to three rendertargets and whant to know how to tell a GPU not to write to the first RT. When you write a shader you can simply output less data than you have RTs (like output a single ...
4
votes
1answer
136 views

PCF shadow shader math causing artifacts

For a while now I used PCSS for my shadow technique of choice until I discovered a type of percentage closer filtering. This method creates really smooth shadows and with hopes of improving ...
14
votes
1answer
651 views

Rendering oily/polluted water?

Any shader wizards out there have an idea of how to achieve an oily/polluted water effect, similar to this: Ideally, the water would not be uniformly oily, but instead the oil could be generated ...
1
vote
1answer
191 views

HLSL What you get when you subtract world position from InvertViewProjection.Translation?

In one of NVIDIA's Vertex shaders (the metal one) I found the following code: // transform object normals, tangents, & binormals to world-space: float4x4 WorldITXf : WorldInverseTranspose < ...
0
votes
0answers
156 views

Radiosity using a hemisphere

I'm working on a radiosity processor. I'm projecting scene geometry onto a hemisphere at a high order of tessellation during a visibility pass onto a 1024x1024 render target. The problem is that the ...
1
vote
0answers
155 views

write to depth buffer while using multiple render targets

Presently my engine is set up to use deferred shading. My pixel shader output struct is as follows: struct GBuffer { float4 Depth : DEPTH0; //depth render target float4 Normal : COLOR0; ...
1
vote
2answers
693 views

How AlphaBlend Blendstate works in XNA 4 when accumulighting light into a RenderTarget?

I am using a Deferred Rendering engine from Catalin Zima's tutorial: His lighting shader returns the color of the light in the rgb channels and the specular component in the alpha channel. Here is ...
5
votes
1answer
273 views

What light attenuation function does UDK use?

I'm a big fan of the light attenuation in UDK. Traditionally I've always used the constant-linear-quadratic falloff function to control how "soft" the falloff is, which gives three values to play ...
0
votes
1answer
110 views

HLSL How to flip geometry horizontally

I want to flip my asymmetric 3d model horizontally in the vertex shader alongside an arbitrary plane parallel to the YZ plane. This should switch everything for the model from the left hand side to ...
2
votes
1answer
124 views

What's the difference between Textures and VertexTextures in XNA?

The GraphicsDevice class of XNA has the properties Textures and VertexTextures. What is the exact difference? I don't really understand what MSDN tells me about this. I usually use Effect parameters ...
2
votes
2answers
1k views

Computing pixel's screen position in a vertex shader: right or wrong?

I am building a deferred rendering engine and I have a question. The article I took the sample code from suggested computing screen position of the pixel as follows: VertexShaderFunction() { ... ...
9
votes
1answer
299 views

Fast lighting with multiple lights

How can I implement fast lighting with multiple lights? I don't want to restrain the player, he can place an unlimited number and possibly overlapping (point) lights into the level. The problem is ...
3
votes
1answer
152 views

Rasterization Rules and States

This thread directly concerns lightmap generation; however, indirectly, the rasterization of polygons by the GPU. I am currently generating lightmaps using a pixel shader. To the shader I send 3 ...
5
votes
1answer
1k views

What does ddx (hlsl) actually do?

I'm a bit confused. The official documentation (http://msdn.microsoft.com/en-us/library/windows/desktop/bb509588(v=vs.85).aspx) says that ddx(input) is the partial derivative of the input with ...
0
votes
0answers
87 views

How to encode float3 into float2 and back again in HLSL?

Good afternoon, I am looking to offload some 3D calculations to the GPU without raising my requirements to DX10. Specifically, I am generating densities in 64x64x64 3D blocks, which fit nicely into ...
0
votes
1answer
113 views

Storing few values in an int - small gain

This might be a bit hard-to-answer question, but... I had a DirectX::XMFLOAT3 as a vertex attribute. I have changed it to just an int by placing the 3 floats into int (using only 8 bits per float). In ...
0
votes
0answers
104 views

Shadow Mapping Wrong Results

Since 2 days, i'm trying to figure out whats wrong with my shadow shader. The shadow map is drawn correctly, just the projection on to the scene is not working. The Vertex Shader Code seems fine: ...
1
vote
1answer
293 views

Color grading, shaders and 3d textures

I'm trying to implement color correction with the 3d lookup table. The lookup table is actually just a 2d texture 256x16 and consists of 16 squares which one is 16x16. When it comes to rendering, I ...
0
votes
2answers
338 views

HLSL's Tex2D for GLSL?

I am trying to port a HLSL shader to GLSL. I'm just not quite sure how to convert this line: outA += Input.Color.a * tex2D(s, Input.TexCoord.xy + float2(-4.0 * pxSz.x * blurSize,0)).a * 0.05; ...
5
votes
1answer
488 views

What does HLSL's tex2D return at (0,0)?

I'm trying to understand the mapping of texels to pixels, especially in the context of pixel shaders. I already found out the following: When I define a standard quad with vertices at integer ...
2
votes
2answers
176 views

XNA hlsl tex2D() only reads 3 channels from normal maps and specular maps

Our engine uses deferred rendering and at the main draw phase gathers plenty of data from the objects it draws. In order to save on tex2D calls, we packed our objects' specular maps with all sorts of ...
12
votes
1answer
309 views

Accounting for waves when doing planar reflections

I've been studying Nvidia's examples from the SDK, in particular the Island11 project and I've found something curious about a piece of HLSL code which corrects the reflections up and down depending ...
2
votes
1answer
199 views

Hemispherical Projection

I'm trying to implement a radiosity processor. I'm aware of many places online to find information about radiosity. I found a great source on NVidia's website is GPU Gems - Chapter 39 . On this page ...
0
votes
1answer
363 views

XNA & HLSL - rendering a model with its original materials (colors)

I am currently trying to code my own HLSL effect file, in order to render an FBX model I made with Autodesk maya, and to which I have applied some materials (colors). before trying to write an effect ...
2
votes
1answer
84 views

Write colors with alphablending but don't write into the alpha channel

I am using XNA 4.0, hence DX9 and HLSL. I have a RenderTarget2D "MAIN" that I want to add semi-transparent objects "TRANS" to. I want them to blend with MAIN using the TRANS's alpha and inverseAlpha ...
1
vote
1answer
513 views

Using multiple passes in OpenCL .net

I'm new to opencl but I have some experience using HLSL. In HLSL multiple passes are used when you need to finish a computation before moving on to the next step. I would like to know how this sort ...
1
vote
1answer
229 views

HLSL Textured Light: outputs only a specific part of the texture (new problem)

Problem 1 I am trying to create a spotlight that instead of giving the circle within the spotlight a simple color, applies a texture to it. However, where the texture is supposed to be is only a ...
0
votes
1answer
1k views

HLSL Gaussian blur pixelshader: blur is not occurring

I am trying to use postprocessing to create a gaussian blur, however, no blur is to be seen, what am I doing wrong? I have included the full code at the bottom of this post in a google docs link, but ...
3
votes
2answers
73 views

Local shape color blending

I am trying to implement this in Unity 4 Pro. But I am stuck in the blending part. I don't understand how you could blend multiples textures/colors using multiples volumes on an object. How could you ...
1
vote
1answer
1k views

HLSL grayscale pixel shader: How to get the original colors of the model?

The following code gives me a completely black colored model, while it should be a model shaded in greyscale: float4 SimplePixelShader(VertexShaderOutput input) : COLOR0 { //some lambertian ...
2
votes
2answers
384 views

How do I rotate a single object in HLSL?

I have a World with a 3D model of a head in it and that World rotates, like such: protected override void Update(GameTime gameTime) { //other stuff angle += 0.00005f; //more other stuff ...
0
votes
0answers
64 views

XNA HLSL no model textures

I am using XNA and HLSL to render all the models in my game, so far there is only one, a flashlight. My flashlight model is a .fbx file type, and it loads the model in the game perfectly fine. ...
2
votes
1answer
269 views

What is this alpha blending result?

I'm having an exam soon and got a problem with one alpha blending exercise: BlendState BS3 { BlendEnable[0] = TRUE; SrcBlend[0] = ONE; SrcBlendAlpha[0] = ZERO; ...
3
votes
1answer
245 views

Adding false if statement to pixel shader produces a lag

One of lines in pixel shader produces a lag (lower fps). I can't understand why. if (TextureEnabled) color *= texDiffuse.Sample(texDiffuseSam, input.UV); Interesting fact is: TextureEnabled is ...
4
votes
1answer
122 views

Masking an area inside/outside a line strip

I have some point lights in my game which are just sprites implemented with help of HLSL. Currently I'm trying to implement dynamic shadows and I managed to make the program calculate the area in ...
0
votes
1answer
135 views

How to control in the vertex shader where pixel ends up in the renderTarget?

What if I have an arbitrary renderTarget, that is smaller than the screen (say it is 1x1 pixel) and I want to make sure in the VertexShaderFunction that all my pixels end up exactly in that 1 pixel ...
1
vote
1answer
336 views

Which coordinate space is the canonical default for each shader pipeline stage?

I'm working with Direct3D 11 and HLSL. I use four different shaders (vertex, hull, domain and pixel). I always have troubles using the right coordinate space in my shaders. Could somebody identify ...
2
votes
1answer
518 views

GPGPU Programming using HLSL and XNA

XNA Newbie question: I'm trying to get the GPU to perform some calculations for me. I'm trying to figure out how to send some data to the GPU, get the GPU to process it, then get the result back. ...
4
votes
2answers
332 views

Calculate mipmap level in a loop with varying iteration?

How can I calculate the correct mipmap level in a shader? It needs to be used in a loop which runs a variable number of times so the compiler will not allow me to use Sample or the derivative ...
2
votes
0answers
314 views

XNA 4.0 Pixel Shader 3.0 Exact Texture Lookup/Sample Issue

I am stuck on trying to solve this problem. I originally had some shaders written that worked for XNA 3.1, but after converting to XNA 4.0 they would no longer compile due to instruction counts, flow ...
5
votes
2answers
500 views

XNA 3.1 to 4.0 Vertex Shader Not Drawing

I have recently been converting our XNA 3.1 game to XNA 4.0 and am stuck on the shaders. I have the game running, but nothing is drawing to the screen, except things not using a shader. This is only ...
2
votes
0answers
126 views

Stereo 3D: drawing 2D elements at apparent screen depth

I'm developing an application making use of DirectX11's stereoscopic features. At such I am not relying on nVidia's automatic implementation. That means I have to replicate a way to render 2d elements ...
3
votes
1answer
168 views

When are HLSL literals taken as a float and integer?

float2 uv = float2(fX % 1, fY % 1) * 1/16; In the above example 1/16 is treated as a float, multiplying the float2 by 0.0625, but in: float2 uv = float2(fX % 1, fY % 1) * 1/16 + float2(1/16,0); ...
2
votes
1answer
73 views

Is it possible to retrieve shader function names associated with a technique pass using the DirectX Effect API?

For example, given the pass pass p0 { SetVertexShader(CompileShader(vs_4_0, VSFunction())) SetPixelShader(CompileShader(ps_4_0, PSFunction())) } Ss it possible to retrieve the names ...
2
votes
2answers
166 views

Are global shader variables slower than texture look ups?

I want to send quite a bit of data to the GPU, the data will never change (or will change very rarely) after it has been created. Is there a performance impact to using global shader variables or ...
0
votes
1answer
185 views

Volume raycaster problems HLSL

Hi this is my first question here so if I fail to include some necessary piece of information please dont rip my head off. ^^ I can't seem to get my volume raycaster to workt properly. I've been ...
0
votes
1answer
76 views

Vertex and Fragment Shader worldNormal

How to access/calculate worldNormal in a Vertex and Fragment shader ? Thanks a lot !
0
votes
1answer
136 views

Angle to Vector3?

I am working on getting my directional lights to match the sun in my atmospheric scattering shader. I have a float that ranges from 0 to 6.28 (TwoPi). How would I calculate a vector3 from this angle? ...