Use waitAndAcquireSwapchainTexture in examples

Non-blocking acquire leaves a command buffer in flight with no swapchain
texture; submitting it is wasteful and skipping rendering while still
proceeding through the frame loop is fragile. Block until the swapchain
is ready instead.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: jdolan

Examples/Hello.c

@@ -184,33 +184,32 @@ int main(int argc, char **argv) {
 		CommandBuffer *cmd = $(renderDevice, acquireCommandBuffer);
 
 		SwapchainTexture swapchain = { 0 };
-    if ($(cmd, acquireSwapchainTexture, window, &swapchain)) {
-
-      float4x4 modelView = float4x4_rotation(angleX, float3_new(1.f, 0.f, 0.f));
-      modelView = float4x4_mul(float4x4_rotation(angleY, float3_new(0.f, 1.f, 0.f)), modelView);
-      modelView = float4x4_mul(float4x4_translation(float3_new(0.f, 0.f, -2.5f)), modelView);
-      const float4x4 projection = float4x4_perspective(45.f, (float) swapchain.size.w / (float) swapchain.size.h, 0.01f, 100.f);
-      const float4x4 modelViewProjection = float4x4_mul(projection, modelView);
-
-      SDL_GPUColorTargetInfo colorTarget = {
-        .texture = swapchain.texture,
-        .clear_color = { 0.1f, 0.1f, 0.2f, 1.0f },
-        .load_op = SDL_GPU_LOADOP_CLEAR,
-        .store_op = SDL_GPU_STOREOP_STORE,
-      };
-
-      SDL_GPUDepthStencilTargetInfo depthTarget = $(framebuffer, depthTargetInfo, SDL_GPU_LOADOP_CLEAR, SDL_GPU_STOREOP_DONT_CARE, 1.f);
-
-      RenderPass *renderPass = $(cmd, beginRenderPass, &colorTarget, 1, &depthTarget);
-      $(renderPass, bindPipeline, pipeline);
-      $(renderPass, bindVertexBuffers, 0, &(SDL_GPUBufferBinding) {
-        .buffer = vertexBuffer,
-        .offset = 0,
-      }, 1);
-      $(cmd, pushVertexUniformData, 0, modelViewProjection.f, sizeof(modelViewProjection));
-      $(renderPass, drawPrimitives, (Uint32) SDL_arraysize(vertex_data), 1, 0, 0);
-      release(renderPass);
-    }
+		$(cmd, waitAndAcquireSwapchainTexture, window, &swapchain);
+
+		float4x4 modelView = float4x4_rotation(angleX, float3_new(1.f, 0.f, 0.f));
+		modelView = float4x4_mul(float4x4_rotation(angleY, float3_new(0.f, 1.f, 0.f)), modelView);
+		modelView = float4x4_mul(float4x4_translation(float3_new(0.f, 0.f, -2.5f)), modelView);
+		const float4x4 projection = float4x4_perspective(45.f, (float) swapchain.size.w / (float) swapchain.size.h, 0.01f, 100.f);
+		const float4x4 modelViewProjection = float4x4_mul(projection, modelView);
+
+		SDL_GPUColorTargetInfo colorTarget = {
+			.texture = swapchain.texture,
+			.clear_color = { 0.1f, 0.1f, 0.2f, 1.0f },
+			.load_op = SDL_GPU_LOADOP_CLEAR,
+			.store_op = SDL_GPU_STOREOP_STORE,
+		};
+
+		SDL_GPUDepthStencilTargetInfo depthTarget = $(framebuffer, depthTargetInfo, SDL_GPU_LOADOP_CLEAR, SDL_GPU_STOREOP_DONT_CARE, 1.f);
+
+		RenderPass *renderPass = $(cmd, beginRenderPass, &colorTarget, 1, &depthTarget);
+		$(renderPass, bindPipeline, pipeline);
+		$(renderPass, bindVertexBuffers, 0, &(SDL_GPUBufferBinding) {
+			.buffer = vertexBuffer,
+			.offset = 0,
+		}, 1);
+		$(cmd, pushVertexUniformData, 0, modelViewProjection.f, sizeof(modelViewProjection));
+		$(renderPass, drawPrimitives, (Uint32) SDL_arraysize(vertex_data), 1, 0, 0);
+		release(renderPass);
 
 		$(cmd, submit);
 		release(cmd);

Examples/HelloCompute.c

@@ -144,12 +144,7 @@ int main(int argc, char **argv) {
 
 		CommandBuffer *cmd = $(renderDevice, acquireCommandBuffer);
 		SwapchainTexture swapchain = { 0 };
-
-		if (!$(cmd, acquireSwapchainTexture, window, &swapchain)) {
-			$(cmd, cancel);
-			release(cmd);
-			continue;
-		}
+		$(cmd, waitAndAcquireSwapchainTexture, window, &swapchain);
 
 		float time = (float) (SDL_GetTicks() - startTicks) / 1000.0f;
 		$(cmd, pushComputeUniformData, 0, &time, sizeof(time));