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/*
See LICENSE folder for this sample’s licensing information.
Abstract:
Metal shaders used for this sample
*/
#include <metal_stdlib>
using namespace metal;
// Include header shared between this Metal shader code and C code executing Metal API commands.
#include "AAPLShaderTypes.h"
// Vertex shader outputs and fragment shader inputs
struct RasterizerData
{
// The [[position]] attribute of this member indicates that this value
// is the clip space position of the vertex when this structure is
// returned from the vertex function.
float4 position [[position]];
// Since this member does not have a special attribute, the rasterizer
// interpolates its value with the values of the other triangle vertices
// and then passes the interpolated value to the fragment shader for each
// fragment in the triangle.
float4 color;
};
vertex RasterizerData
vertexShader(uint vertexID [[vertex_id]],
constant AAPLVertex *vertices [[buffer(AAPLVertexInputIndexVertices)]],
constant vector_uint2 *viewportSizePointer [[buffer(AAPLVertexInputIndexViewportSize)]])
{
RasterizerData out;
// Index into the array of positions to get the current vertex.
// The positions are specified in pixel dimensions (i.e. a value of 100
// is 100 pixels from the origin).
float2 pixelSpacePosition = vertices[vertexID].position.xy;
// Get the viewport size and cast to float.
vector_float2 viewportSize = vector_float2(*viewportSizePointer);
// To convert from positions in pixel space to positions in clip-space,
// divide the pixel coordinates by half the size of the viewport.
out.position = vector_float4(0.0, 0.0, 0.0, 1.0);
out.position.xy = pixelSpacePosition / (viewportSize / 2.0);
// Pass the input color directly to the rasterizer.
out.color = vertices[vertexID].color;
return out;
}
fragment float4 fragmentShader(RasterizerData in [[stage_in]])
{
// Return the interpolated color.
return in.color;
}
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