refactoring renderer

src/soft/device/fragment.zig

@@ -0,0 +1,45 @@
+const std = @import("std");
+const vk = @import("vulkan");
+const base = @import("base");
+const zm = base.zm;
+const spv = @import("spv");
+
+const lib = @import("../lib.zig");
+
+const Renderer = @import("Renderer.zig");
+const SoftImage = @import("../SoftImage.zig");
+
+const VkError = base.VkError;
+const SpvRuntimeError = spv.Runtime.RuntimeError;
+
+pub fn shaderInvocation(allocator: std.mem.Allocator, draw_call: *Renderer.DrawCall, batch_id: usize, position: zm.F32x4, inputs: [spv.SPIRV_MAX_OUTPUT_LOCATIONS][]const u8) SpvRuntimeError!zm.F32x4 {
+    _ = position;
+    const pipeline = draw_call.renderer.state.pipeline orelse return zm.f32x4s(0.0);
+
+    const shader = pipeline.stages.getPtrAssertContains(.fragment);
+    const rt = &shader.runtimes[batch_id];
+
+    const entry = try rt.getEntryPointByName(shader.entry);
+    const output_result = try rt.getResultByLocation(0, .output);
+
+    for (0..spv.SPIRV_MAX_OUTPUT_LOCATIONS) |location| {
+        const result_word = rt.getResultByLocation(@intCast(location), .input) catch |err| switch (err) {
+            SpvRuntimeError.NotFound => continue,
+            else => return err,
+        };
+        try rt.writeInput(inputs[location], result_word);
+        allocator.free(inputs[location]);
+    }
+
+    rt.callEntryPoint(allocator, entry) catch |err| switch (err) {
+        // Some errors can be safely ignored
+        SpvRuntimeError.OutOfBounds,
+        SpvRuntimeError.Killed,
+        => {},
+        else => return err,
+    };
+
+    var color = zm.f32x4s(0.0);
+    try rt.readOutput(std.mem.asBytes(&color), output_result);
+    return std.math.clamp(color, zm.f32x4s(0.0), zm.f32x4s(1.0));
+}