Graphics Programming I - Hardware Rasterization Part II PDF

GRAPHICS PROGRAMMING I HARDWARE RASTERIZATION PART II Graphics Programming 1 – Hardware Rasterization Part II DirectX: Camera Last week we rendered a triangle that was defined in homogenous coordinates (NDC). Let’s adjust our code and render a triangle that is defined in world spa...

GRAPHICS PROGRAMMING I HARDWARE RASTERIZATION PART II Graphics Programming 1 – Hardware Rasterization Part II DirectX: Camera Last week we rendered a triangle that was defined in homogenous coordinates (NDC). Let’s adjust our code and render a triangle that is defined in world space. Vector3(0, 3, 2), Vector3(3, -3, 2) & Vector3(-3, -3, 2), using index buffer { 0, 1, 2 } Just as with the software rasterizer, we need to transform our vertices into projection space (before the perspective divide) before we pass it into the rasterization stage. Luckily for us, the rasterizer stage is done by DirectX, this includes the perspective divide. We just need to define the correct matrix. You’ve already done this! We must make a WorldViewProjection matrix, pass it to our shader and transform every vertex that passes the vertex shader stage. As with the software rasterizer, we create the View matrix based on our camera’s ONB and our Projection matrix based on the camera settings. Add a camera class to your project and make sure you have the following functions: Matrix GetViewMatrix() Matrix GetProjectionMatrix() You can also implement/use the Matrix::CreateLookAtLH & Matrix::CreatePerspectiveFovLH functions Graphics Programming 1 – Hardware Rasterization Part II DirectX: Camera Next, we need to “transfer” the matrix from CPU to GPU so we can use it in our shader. As mentioned last week, setting up the pipeline for a draw call is done through the device context using resource views. When using shaders, there are several options, but these are the common ones: Constant Buffer View : ID3D11Buffer → CBuffer and TBuffer Unordered Access View (UAV) : ID3D11UnorderedAccessView Shader Resource View (SRV) : ID3D11ShaderResourceView We are going to use the DX11Effects framework which has some predefined types that will make our lives a bit easier. Update your shader by adding a global variable that represents your WorldViewProjection matrix. In your effect class get a ID3DX11EffectMatrixVariable that links to this variable. You can do this using the following code: Graphics Programming 1 – Hardware Rasterization Part II DirectX: Camera Inside your Vertex Shader Function, you now have to transform the input Position with the WorldViewProjection matrix (https://learn.microsoft.com/en-us/windows/win32/direct3dhlsl/dx-graphics-hlsl-mul) The last thing you need to do is update the data every frame using the SetMatrix(…) function of the (c++ side) matrix effect variable, same as you update the vertex buffer etc. Using your camera, you can build the WorldViewProjection matrix that you then pass to that function. Hint: you’ll have to reinterpret the Matrix data… Camera FovAngle: 45.f Origin: {0.f, 0.f, -10.f} Graphics Programming 1 – Hardware Rasterization Part II DirectX: Textures Let’s upgrade our triangle into a quad, using texture (UV) coordinates, to be able to preview a texture. Just as with the software rasterizer, update your vertex structure accordingly (in both C++ and HLSL). For the UV coordinates you can use the semantic TEXCOORD. This also affects your vertex input layout ! Fix this by adding another element! ☺ As with the software rasterizer, create a texture class that loads a texture from memory using IMG_Load. The only difference is that we now need to create a DirectX resource and a resource view. Do this resource/resource view creation when you load the texture, so only once! After pushing the data from the SDL_Surface to the resource, the SDL_Surface is no longer needed in memory, thus free it using SDL_FreeSurface. Make sure your texture class has a getter function to retrieve the ID3D11ShaderResourceView you’ve just loaded! Graphics Programming 1 – Hardware Rasterization Part II DirectX: Textures Graphics Programming 1 – Hardware Rasterization Part II DirectX: Textures We create a Texture2D, but there are different types of textures in DirectX: Texture1D Texture2D TextureCube Texture3D … → https://docs.microsoft.com/en-us/windows/win32/direct3dhlsl/dx-graphics-hlsl-to-type It’s important to realize they are just like arrays! Graphics Programming 1 – Hardware Rasterization Part II DirectX: Textures Texture can also have mipmaps. A mipmap is a sequence of textures, each of which is a progressively lower resolution representation of the same image. A high-resolution mipmap is used for objects that are close to the viewer. You can create them through the Device Context using GenerateMips. Mipmapping improves the quality of rendered textures at the expense of using more memory! Graphics Programming 1 – Hardware Rasterization Part II DirectX: Textures Finally, update your shader to accept a Texture2D shader resource view and update your Effect class to create a shader resource variable (ID3DX11EffectShaderResourceVariable) so we can push the data to the GPU. This type is from the external Effect Framework, just as the matrix! Make sure to bind the ShaderResourceView to the corresponding ID3D11ShaderResourceView effect variable, this can be achieved by using the SetResource(…) function. Graphics Programming 1 – Hardware Rasterization Part II DirectX: Textures Don’t forget to release all the resources and resource views in the destructor! ☺ As you can see, DirectX is all about resource management and setting up the state of the pipeline before a draw call. It’s not that different from our software rasterizer. So how do we render now? How do we sample in our shader? In HLSL you must define how you want to sample using a SamplerState. This state is just a struct that keeps track of all the settings. We will again use a global variable. https://docs.microsoft.com/en-us/windows/win32/direct3dhlsl/dx-graphics-hlsl-to-sample Let’s go over some of these settings. Graphics Programming 1 – Hardware Rasterization Part II DirectX: Textures 1. High Quality Elliptical Texture Filtering on GPU Graphics Programming 1 – Hardware Rasterization Part II DirectX: Textures Graphics Programming 1 – Hardware Rasterization Part II DirectX: Textures Graphics Programming 1 – Hardware Rasterization Part II DirectX: Textures With the SamplerState defined in HLSL you can now sample the Texture2D using the Sample(…) function. Do this in the PixelShader and return the float4 value. https://docs.microsoft.com/en-us/windows/win32/direct3dhlsl/dx-graphics-hlsl-to-sample Load the texture from a few weeks ago, update the shader variables and draw the quad. Graphics Programming 1 – Hardware Rasterization Part II DirectX: Textures Implement three Sampler States with different Filtering Methods: Point, Linear and Anisotropic. Make sure you can toggle between them using the ‘F2’ key. Hint: define three different techniques with three different pixel shaders that use a different sample method. Do reuse calculations in the pixel shader by writing separate functions. ☺ Capture all techniques in the effect class and when rendering, render using the correct technique! Basically, change the code below allowing you to toggle between techniques. Alternative : SamplerStates can also be changed/updated from c++ (this way you only need a single Technique of course) [ID3D11SamplerState] Graphics Programming 1 – Hardware Rasterization Part II DirectX: Textures Graphics Programming 1 – Hardware Rasterization Part II DirectX: Textures Graphics Programming 1 – Hardware Rasterization Part II DirectX: Textures Graphics Programming 1 – Hardware Rasterization Part II DirectX: Textures Anisotropic Mipmapping Allows to keep a higher resolution in one axis while reducing the other one. https://commons.wikimedia.org/wiki/File:MipMap_Example_STS101_Anisotropic.png Graphics Programming 1 – Hardware Rasterization Part II DirectX: Mesh Use the vehicle mesh and diffuse texture from the previous weeks. Load the model with your parser and use those vertex and index buffers. Hint: disable the normal/tangent parsing for now. (Pos/uv & DiffuseMap only) Camera FovAngle: 45.f Origin: {0.f, 0.f, -50.f} Rotation: 90DEG/S Graphics Programming 1 – Hardware Rasterization Part II GOOD LUCK! Graphics Programming 1 – Hardware Rasterization Part II