ld58/code/draw/core.c

void D_Begin(D_Context *draw, Vk_Frame *frame, U32 max_rects) {
	Vk_Buffer *rbo   = &frame->rbo;

	draw->rbo       = rbo;
	draw->n_rects   = 0;
	draw->max_rects = max_rects;
	draw->rects     = rbo->data;
}

void D_End(D_Context *draw, Vk_Frame *frame) {
	VkCommandBuffer cmd = frame->cmd;
	Vk_Pipeline *basic  = &draw->pipelines[0];

	// We can probably stop doing this at some point
	VkDescriptorSet set;
	VkDescriptorSetAllocateInfo alloc_info = { 0 };
	alloc_info.sType              = VK_STRUCTURE_TYPE_DESCRIPTOR_SET_ALLOCATE_INFO;
	alloc_info.descriptorPool     = frame->descriptors;
	alloc_info.descriptorSetCount = 1;
	alloc_info.pSetLayouts        = &basic->layout.set;

	vk.AllocateDescriptorSets(vk.device, &alloc_info, &set);

	// 'update' the descriptor sets for binding
	M_TempScope(0, 0) {
		VkWriteDescriptorSet writes[2] = { 0 };

		VkDescriptorBufferInfo rbo_info = { 0 };
		rbo_info.buffer = draw->rbo->handle;
		rbo_info.offset = 0;
		rbo_info.range  = VK_WHOLE_SIZE;

		VkDescriptorImageInfo *image_info = M_ArenaPush(temp.arena, VkDescriptorImageInfo, .count = draw->n_images);

		for (U32 it = 0; it < draw->n_images; ++it) {
			image_info[it].imageView   = draw->images[it].image.view;
			image_info[it].sampler     = vk.sampler;
			image_info[it].imageLayout = VK_IMAGE_LAYOUT_SHADER_READ_ONLY_OPTIMAL;
		}

		writes[0].sType           = VK_STRUCTURE_TYPE_WRITE_DESCRIPTOR_SET;
		writes[0].dstSet          = set;
		writes[0].dstBinding      = 0;
		writes[0].descriptorCount = 1;
		writes[0].descriptorType  = VK_DESCRIPTOR_TYPE_STORAGE_BUFFER;
		writes[0].pBufferInfo     = &rbo_info;

		writes[1].sType           = VK_STRUCTURE_TYPE_WRITE_DESCRIPTOR_SET;
		writes[1].dstSet          = set;
		writes[1].dstBinding      = 1;
		writes[1].descriptorCount = draw->n_images;
		writes[1].descriptorType  = VK_DESCRIPTOR_TYPE_COMBINED_IMAGE_SAMPLER;
		writes[1].pImageInfo      = image_info;

		vk.UpdateDescriptorSets(vk.device, ArraySize(writes), writes, 0, 0);
	}

	vk.CmdBindPipeline(cmd, VK_PIPELINE_BIND_POINT_GRAPHICS, basic->handle);
	vk.CmdBindDescriptorSets(cmd, VK_PIPELINE_BIND_POINT_GRAPHICS, basic->layout.pipeline, 0, 1, &set, 0, 0);
	vk.CmdPushConstants(cmd, basic->layout.pipeline, VK_SHADER_STAGE_VERTEX_BIT, 0, sizeof(Mat4x4F), &draw->camera->proj.fwd);

	VkViewport viewport = { 0, 0, (F32) draw->window_width, (F32) draw->window_height, 0.0f, 1.0f };
	VkRect2D   scissor  = { 0, 0, draw->window_width, draw->window_height };

	vk.CmdSetViewport(cmd, 0, 1, &viewport);
	vk.CmdSetScissor(cmd, 0, 1, &scissor);

	vk.CmdDraw(cmd, 6, draw->n_rects, 0, 0);
}

internal U32 V4f_UnormColour(V4f c) {
	// @Todo: SRGB handling
	U32 result =
		((U8) (255.0f * c.a)) << 24 |
		((U8) (255.0f * c.r)) << 16 |
		((U8) (255.0f * c.g)) <<  8 |
		((U8) (255.0f * c.b)) <<  0;

	return result;
}

void _D_Rect(D_Context *draw, D_RectOpts *opts) {
	if (draw->n_rects < draw->max_rects) {
		D_Rect *rect = &draw->rects[draw->n_rects];

		rect->texture = opts->texture;

		rect->x = opts->p.x;
		rect->y = opts->p.y;

		rect->uv[0] = opts->uv.min.x;
		rect->uv[1] = opts->uv.min.y;
		rect->uv[2] = opts->uv.max.x;
		rect->uv[3] = opts->uv.max.y;

		rect->angle = opts->angle;

		if (opts->flags & D_RECT_PER_VERTEX_COLOUR) {
			rect->c[0] = V4f_UnormColour(opts->vtxc[0]);
			rect->c[1] = V4f_UnormColour(opts->vtxc[1]);
			rect->c[2] = V4f_UnormColour(opts->vtxc[2]);
			rect->c[3] = V4f_UnormColour(opts->vtxc[3]);
		}
		else {
			U32 unorm = V4f_UnormColour(opts->c);

			rect->c[0] = unorm;
			rect->c[1] = unorm;
			rect->c[2] = unorm;
			rect->c[3] = unorm;
		}

		if (opts->flags & D_RECT_IGNORE_ASPECT) {
			rect->w = opts->w;
			rect->h = opts->h;
		}
		else {
			Vk_Image *image = &draw->images[opts->texture].image;

			if (image->width > image->height) {
				rect->w = opts->scale * ((F32) image->width / (F32) image->height);
				rect->h = opts->scale;
			}
			else {
				rect->w = opts->scale;
				rect->h = opts->scale * ((F32) image->height / (F32) image->width);
			}
		}

		draw->n_rects += 1;
	}
}