JarkkoPFC

struct vec2f {float x, y;};
struct vec3f {float x, y, z;};

//============================================================================
// cone_uniform_vector
//============================================================================
// Returns uniformly distributed unit vector on a [0, 0, 1] oriented cone of
// given apex angle and uniform random vector xi ([x, y] in range [0, 1]).
// e.g. cos_half_apex_angle = 0 returns samples on a hemisphere (cos(pi/2)=0),
// while cos_half_apex_angle = -1 returns samples on a sphere (cos(pi)=-1)

JarkkoPFC

struct vec3f {float x, y, z;};
struct vec4f {float x, y, z, w;};
struct mat44f {vec4f x, y, z, w;};

//============================================================================
// sphere_screen_extents
//============================================================================
// Calculates the exact screen extents xyzw=[left, bottom, right, top] in
// normalized screen coordinates [-1, 1] for a sphere in view space. For
// performance, the projection matrix (v2p) is assumed to be setup so that

silvesthu

GPU Optimization for GameDev

Graphics Pipeline / GPU Architecture Overview

• 2011 - A trip through the Graphics Pipeline 2011
• 2015 - Life of a triangle - NVIDIA's logical pipeline
• 2015 - Render Hell 2.0
• 2016 - How bad are small triangles on GPU and why?
• 2017 - GPU Performance for Game Artists
• 2019 - Understanding the anatomy of GPUs using Pokémon
• 2020 - GPU ARCHITECTURE RESOURCES

thefranke

The RSS Endpoint List

Please refer to this blogpost to get an overview.

Replace *-INSTANCE with one of the public instances listed in the scrapers section. Replace CAPITALIZED words with their corresponding identifiers on the website.

Social Media

Twitter

sebbbi

In shader programming, you often run into a problem where you want to iterate an array in memory over all pixels in a compute shader
group (tile). Tiled deferred lighting is the most common case. 8x8 tile loops over a light list culled for that tile. 

Simplified HLSL code looks like this:

Buffer<float4> lightDatas;
Texture2D<uint2> lightStartCounts;
RWTexture2D<float4> output;

[numthreads(8, 8, 1)]

sebbbi

// NOTE: Must bind 8x single mip RWTexture views, because HLSL doesn't have .mips member for RWTexture2D. (SRVs only have .mips member)
// NOTE: globallycoherent attribute is needed. Without it writes aren't guaranteed to be seen by other groups
globallycoherent RWTexture2D<float> MipTextures[8];
RWTexture2D<uint> Counters[8];
groupshared uint CounterReturnLDS;

[numthreads(16, 16, 1)]
void GenerateMipPyramid(uint3 Tid : SV_DispatchThreadID, uint3 Group : SV_GroupId, uint Gix : SV_GroupIndex)
{
	[unroll]

Erkaman

#include <stdio.h>
#include <math.h>

float max(float x, float y) {
    return x > y ? x : y;
}

class vec3 {
public:
    float x;

kayru

struct FloatBits
{
	u32 mantissa : 23;
	u32 exponent : 8;
	u32 sign : 1;
};

template <typename ResultT, typename InputT>
inline ResultT bitCast(InputT v)
{

paniq

Ellipsoid Frustum Intersection

Yesterday I posted a problem to math stack exchange that bothered me for a while now, and right after I've had a few exchanges on Twitter, I got inspired to attempt a solution.

Here it goes. It's 100% untested but I'm fairly certain that it will work.

The problem is about a form of refining raytracing where we render a big list of convex 3D brushes (and I decided to start with Ellipsoids, since they're so useful) to the screen or a shadow map, without any prebuilt accelleration structure. How does it work? Well, if we had a way to figure out for a portion of the frustum whether it contained a brush, we could

1. Start with a very low resolution

romainguy

// From https://github.com/google/filament
float D_GGX(float linearRoughness, float NoH, const vec3 h) {
    // Walter et al. 2007, "Microfacet Models for Refraction through Rough Surfaces"

    // In mediump, there are two problems computing 1.0 - NoH^2
    // 1) 1.0 - NoH^2 suffers floating point cancellation when NoH^2 is close to 1 (highlights)
    // 2) NoH doesn't have enough precision around 1.0
    // Both problem can be fixed by computing 1-NoH^2 in highp and providing NoH in highp as well

    // However, we can do better using Lagrange's identity: