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Juliet/Assets/source/ImGui.vert.hlsl
Patedam 891c404889 Added debug renderer + imgui renderer
All code made by gemini with some help
2026-01-20 22:46:10 -05:00

71 lines
2.2 KiB
HLSL

struct Output
{
float4 Color : TEXCOORD0;
float2 UV : TEXCOORD1;
float4 Position : SV_Position;
};
#include "RootConstants.hlsl"
struct Vertex
{
float2 Pos;
float2 UV;
uint Color;
};
Output main(uint vertexIndex : SV_VertexID)
{
Output output;
// Retrieve the vertex buffer using SM6.6 bindless syntax
ByteAddressBuffer buffer = ResourceDescriptorHeap[BufferIndex];
// Add VertexOffset for indexed drawing with bindless buffers
// (SV_VertexID in indexed draw is raw index from index buffer, doesn't include BaseVertexLocation)
uint actualVertexIndex = vertexIndex + VertexOffset;
// ImDrawVert stride = 20 bytes (Vec2 pos + Vec2 uv + uint color)
uint stride = 20;
uint offset = actualVertexIndex * stride;
float2 pos = asfloat(buffer.Load2(offset));
float2 uv = asfloat(buffer.Load2(offset + 8));
uint col = buffer.Load(offset + 16);
// Unpack color (uint to float4)
// ImGui colors are 0xAABBGGRR (ABGR packed)
// We need to unpack to float4.
// HLSL unpacks as little endian.
// uint 0xAABBGGRR -> byte0=RR, byte1=GG, byte2=BB, byte3=AA
float4 c;
c.x = float(col & 0xFF) / 255.0f;
c.y = float((col >> 8) & 0xFF) / 255.0f;
c.z = float((col >> 16) & 0xFF) / 255.0f;
c.w = float((col >> 24) & 0xFF) / 255.0f;
// Transform
// ImGui sends pixel coordinates.
// We need to transform to NDC [-1, 1].
// PushConstants should contain Scale and Translate.
// float2 Scale = 2.0 / DisplaySize
// float2 Translate = -1.0 - (DisplayPos * Scale)
// We will assume PushConstants are float2 Scale, float2 Translate.
// Struct in RootConstants.hlsl?
// RootConstants.hlsl likely defines `cbuffer PushConstants : register(b0)`.
// Let's assume standard push constants usage.
// Debug.vert.hlsl used `ViewProjection`.
// We need to customize PushConstants or reuse `ViewProjection` slot?
// Juliet uses 128 bytes of push constants.
// We can map float4 ProjectionMatrix (or similar).
// Use Scale and Translate from RootConstants
output.Position = float4(pos * Scale + Translate, 0.0f, 1.0f);
output.Color = c;
output.UV = uv;
return output;
}