improving draw line

src/soft/device/rasterizer/common.zig

@@ -4,10 +4,12 @@ const base = @import("base");
 const zm = base.zm;
 const spv = @import("spv");
 
+const blitter = @import("../blitter.zig");
 const Renderer = @import("../Renderer.zig");
 
 const VkError = base.VkError;
 const F32x4 = zm.F32x4;
+const U32x4 = @Vector(4, u32);
 
 pub const RenderTargetAccess = struct {
     mutex: std.Io.Mutex,
@@ -98,3 +100,43 @@ pub fn interpolateLineOutputs(
 inline fn interpolateF32x4(value0: F32x4, value1: F32x4, value2: F32x4, b0: f32, b1: f32, b2: f32) F32x4 {
     return (value0 * zm.f32x4s(b0)) + (value1 * zm.f32x4s(b1)) + (value2 * zm.f32x4s(b2));
 }
+
+pub fn writeToTargets(
+    outputs: [spv.SPIRV_MAX_OUTPUT_LOCATIONS][@sizeOf(F32x4)]u8,
+    draw_call: *Renderer.DrawCall,
+    color_attachment_access: *const RenderTargetAccess,
+    depth_attachment_access: ?*RenderTargetAccess,
+    x: usize,
+    y: usize,
+    z: f32,
+) VkError!void {
+    const io = draw_call.renderer.device.interface.io();
+
+    const color_offset = @as(usize, @intCast(x)) * color_attachment_access.texel_size + @as(usize, @intCast(y)) * color_attachment_access.row_pitch;
+
+    // After work depth test to avoid overwritten depth pixels during fragment invocations
+    if (depth_attachment_access) |depth| {
+        const depth_offset = @as(usize, @intCast(x)) * depth.texel_size + @as(usize, @intCast(y)) * depth.row_pitch;
+
+        depth.mutex.lock(io) catch return VkError.DeviceLost;
+        defer depth.mutex.unlock(io);
+
+        const depth_value = blitter.readFloat4(depth.base[depth_offset..], depth.format);
+        if (z >= depth_value[0])
+            return;
+        blitter.writeFloat4(zm.f32x4s(z), depth.base[depth_offset..], depth.format);
+
+        // Doubled line to stay inside the critical section
+        if (base.format.isUnnormalizedInteger(color_attachment_access.format)) {
+            blitter.writeInt4(std.mem.bytesToValue(U32x4, &outputs[0]), color_attachment_access.base[color_offset..], color_attachment_access.format);
+        } else {
+            blitter.writeFloat4(std.mem.bytesToValue(F32x4, &outputs[0]), color_attachment_access.base[color_offset..], color_attachment_access.format);
+        }
+    } else {
+        if (base.format.isUnnormalizedInteger(color_attachment_access.format)) {
+            blitter.writeInt4(std.mem.bytesToValue(U32x4, &outputs[0]), color_attachment_access.base[color_offset..], color_attachment_access.format);
+        } else {
+            blitter.writeFloat4(std.mem.bytesToValue(F32x4, &outputs[0]), color_attachment_access.base[color_offset..], color_attachment_access.format);
+        }
+    }
+}