From 2036b60992bcd28d585d237fd0f57243f7675e5f Mon Sep 17 00:00:00 2001 From: skal Date: Fri, 6 Feb 2026 17:27:57 +0100 Subject: feat(particles): Implement transparent circular particles with alpha blending (Task #53) MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit ## Visual Improvements - Particles now render as smooth fading circles instead of squares - Added UV coordinates to vertex shader output - Fragment shader applies circular falloff (smoothstep 1.0 to 0.5) - Lifetime-based fade: alpha multiplied by particle.pos.w (1.0 → 0.0) ## Pipeline Changes - Enabled alpha blending for particle shaders (auto-detected via strstr) - Blend mode: SrcAlpha + OneMinusSrcAlpha (standard alpha blending) - Alpha channel: One + OneMinusSrcAlpha for proper compositing ## Demo Integration - Added 5 ParticleSprayEffect instances at key moments (6b, 12b, 17b, 24b, 56b) - Increased particle presence throughout demo - Particles now more visually impactful with transparency ## Files Modified - assets/final/shaders/particle_render.wgsl: Circular fade logic - src/gpu/gpu.cc: Auto-enable blending for particle shaders - assets/demo.seq: Added ParticleSprayEffect at multiple sequences ## Testing - All 23 tests pass (100%) - Verified with demo64k visual inspection --- src/gpu/gpu.cc | 18 ++++++++++++++++-- 1 file changed, 16 insertions(+), 2 deletions(-) (limited to 'src/gpu/gpu.cc') diff --git a/src/gpu/gpu.cc b/src/gpu/gpu.cc index 1f71711..1d661c7 100644 --- a/src/gpu/gpu.cc +++ b/src/gpu/gpu.cc @@ -105,9 +105,23 @@ RenderPass gpu_create_render_pass(WGPUDevice device, WGPUTextureFormat format, WGPUColorTargetState color_target = {}; color_target.format = format; // Use passed format color_target.writeMask = WGPUColorWriteMask_All; - color_target.blend = nullptr; - // Add additive blending for particles + // Enable alpha blending for transparent effects (particles) + // Check if shader contains "particle" to enable blending + WGPUBlendState blend_state = {}; + blend_state.color.srcFactor = WGPUBlendFactor_SrcAlpha; + blend_state.color.dstFactor = WGPUBlendFactor_OneMinusSrcAlpha; + blend_state.color.operation = WGPUBlendOperation_Add; + blend_state.alpha.srcFactor = WGPUBlendFactor_One; + blend_state.alpha.dstFactor = WGPUBlendFactor_OneMinusSrcAlpha; + blend_state.alpha.operation = WGPUBlendOperation_Add; + + // Enable blending for particle shaders + if (strstr(shader_code, "particle") != nullptr) { + color_target.blend = &blend_state; + } else { + color_target.blend = nullptr; + } WGPUFragmentState fragment_state = {}; fragment_state.module = shader_module; -- cgit v1.2.3