Question

6. Explain the shader stage functionalities on texture mapping in a fixed-function graphics pipeline ?

Subject : Parallel Computer Architecture and Programming

Answer 1

• Explain the shader stage functionalities on texture mapping in a fixed-function graphics pipeline?

• Let’s understand some definition before answering the question to easily understand:
  • This kind of hardware was in style from the first Eighties to the late Nineties.
  • These were fixed-function pipelines that were configurable, however not programmable.
  • What is Texture Mapping?
    • Texture mapping may be a technique for outlining high frequency detail, surface texture, or colour info on a computer-generated graphic or 3D model.

5. Now let’s move to our main Topic:

5. The mounted-function pipeline will specifically what the name suggests; its practicality is fixed.
   • for example, if the pipeline contains a listing of ways to rasterize pure mathematics and shade pixels, that's just about it. you cannot add any longer ways.
   • Although these pipelines were sensible at rendering scenes, they enshrine sure deficiencies.
   • In broad terms, you'll be able to perform linear transformations and so rasterize by texturing, interpolate a colour across a face by combos and permutations of these things.

• In fashionable GPUs, all the pipelines square measure generic, and might run any sort of GPU computer programme code.
• In recent time, the amount of functions of the pipeline square measure several - they are doing vertex mapping, and colour calculation for every constituent, they conjointly support pure mathematics shader (tessellation), and even reason shaders (where the parallel processor is employed to try to a non-graphics job).
• Fixed operate pipelines square measure restricted in their capabilities, however square measure straightforward to style.
• they're not used a lot of in today’s graphics systems. Instead, programmable pipelines victimization OpenGL or DirectX square measure the de-facto standards for contemporary GPUs.

5. Let us perceive the varied stages of the pipeline now:

• The hardware sends commands and knowledge to the GPU host interface. Typically, the commands square measure given by application programs by occupation AN API operate (from a listing of many). A specialised Direct access (DMA) hardware is employed by the host interface to lock the transfer of bulk knowledge to and from the graphics pipeline.
• In the GeForce pipeline, the surface of AN object is drawn as a group of triangles (the GeForce pipeline has been designed to render triangles). The finer the scale of the Triangle, the higher the image quality (you will observe them in older games just like the Tekken 3).
• The vertex management stage receives parameterized triangle knowledge from the host interface (which in-turn receives it from the CPU). Then comes the VT/T&; L stage. It stands for Vertex Shading, rework and Lighting. This stage transforms vertices and assigns every vertex value for a few parameters, like colours, texture coordinates, normal and tangents. The constituent shader hardware will the shading (the vertex shader assigns a colour price to every vertex; however, colouring is finished later).
• The triangle setup stage is employed to interpolate colours and different vertex parameters to those pixels that square measure touched by the Triangle (the triangle setup stage truly determines the sting equations. it's the formation stage that interpolates).
• The shader stage offers the constituent its final colour. There square measure several ways to realize this, apart kind interpolations. a number of them embrace texture mapping, per-pixel lighting, reflections, etc.
• Shading Interpolation:
  • It is primarily assignment a colour to every vertex of a triangle on the surface (represented by plane figure meshes, in our case, the plane figure may be a triangle), and linearly interpolating for every constituent lined by the Triangle. There square measure many types to the present, like flat shading, Gouraud shading and Phong shading.