Vulkan再探（11）：立方体贴图数组

08/20/2020

立方体贴图数组

创建纹理贴图

//提取信息
cubeMapArray.width = ktxTexture->baseWidth;
cubeMapArray.height = ktxTexture->baseHeight;
cubeMapArray.mipLevels = ktxTexture->numLevels;
cubeMapArray.layerCount = ktxTexture->numLayers;

图像

立方体自带六个面

// Cube faces count as array layers in Vulkan
imageCreateInfo.arrayLayers = 6 * cubeMapArray.layerCount;
// This flag is required for cube map images
imageCreateInfo.flags = VK_IMAGE_CREATE_CUBE_COMPATIBLE_BIT;

拷贝区域

/*
	We now copy the parts that make up the cube map array to our image via a command buffer
	Cube map arrays in ktx are stored with a layout like this:
	- Mip Level 0
		- Layer 0 (= Cube map 0)
			- Face +X
			- Face -X
			- Face +Y
			- Face -Y
			- Face +Z
			- Face -Z
		- Layer 1 (= Cube map 1)
			- Face +X
			...
	- Mip Level 1
		- Layer 0 (= Cube map 0)
			- Face +X
			...
		- Layer 1 (= Cube map 1)
			- Face +X
			...
*/

// Setup buffer copy regions for each face including all of its miplevels
std::vector<VkBufferImageCopy> bufferCopyRegions;
uint32_t offset = 0;
for (uint32_t face = 0; face < 6; face++) {
	for (uint32_t layer = 0; layer < ktxTexture->numLayers; layer++) {
		for (uint32_t level = 0; level < ktxTexture->numLevels; level++) {
			ktx_size_t offset;
			KTX_error_code ret = ktxTexture_GetImageOffset(ktxTexture, level, layer, face, &offset);
			assert(ret == KTX_SUCCESS);
			VkBufferImageCopy bufferCopyRegion = {};
			bufferCopyRegion.imageSubresource.aspectMask = VK_IMAGE_ASPECT_COLOR_BIT;
			bufferCopyRegion.imageSubresource.mipLevel = level;
			bufferCopyRegion.imageSubresource.baseArrayLayer = layer * 6 + face;
			bufferCopyRegion.imageSubresource.layerCount = 1;
			bufferCopyRegion.imageExtent.width = ktxTexture->baseWidth >> level;
			bufferCopyRegion.imageExtent.height = ktxTexture->baseHeight >> level;
			bufferCopyRegion.imageExtent.depth = 1;
			bufferCopyRegion.bufferOffset = offset;
			bufferCopyRegions.push_back(bufferCopyRegion);
		}
	}
}

图像视图

// Create the image view for a cube map array
VkImageViewCreateInfo view = vks::initializers::imageViewCreateInfo();
view.viewType = VK_IMAGE_VIEW_TYPE_CUBE_ARRAY;
view.format = format;
view.components = { VK_COMPONENT_SWIZZLE_R, VK_COMPONENT_SWIZZLE_G, VK_COMPONENT_SWIZZLE_B, VK_COMPONENT_SWIZZLE_A };
view.subresourceRange = { VK_IMAGE_ASPECT_COLOR_BIT, 0, 1, 0, 1 };
view.subresourceRange.layerCount = 6 * cubeMapArray.layerCount;
view.subresourceRange.levelCount = cubeMapArray.mipLevels;
view.image = cubeMapArray.image;
VK_CHECK_RESULT(vkCreateImageView(device, &view, nullptr, &cubeMapArray.view));

着色器

片元着色器

#version 450

layout (binding = 1) uniform samplerCubeArray samplerCubeMapArray;

layout (binding = 0) uniform UBO
{
	mat4 projection;
	mat4 model;
	mat4 invModel;
	float lodBias;
	int cubeMapIndex;
} ubo;

layout (location = 0) in vec3 inUVW;

layout (location = 0) out vec4 outFragColor;

void main() 
{
	outFragColor = textureLod(samplerCubeMapArray, vec4(inUVW, ubo.cubeMapIndex), ubo.lodBias);
}

• 立方体数组
• 采样器需要知道采样的数组下标