添加双纹理采样

vulkan/AppBase.cpp

@@ -335,4 +335,113 @@ void AppBase::pickPhysicalDevice(VkPhysicalDevice& physicalDevice, VkSurfaceKHR&
 	if (physicalDevice == VK_NULL_HANDLE) {
 		throw std::runtime_error("failed to find a suitable GPU!");
 	}
+}
+
+
+// 计算面的法线
+void AppBase::calculateFaceNormal(const TextureLoadingVertexStructure& v0,
+	const TextureLoadingVertexStructure& v1,
+	const TextureLoadingVertexStructure& v2,
+	float* outNormal)
+{
+	// 计算两个边向量
+	float edge1[3] = { v1.pos[0] - v0.pos[0], v1.pos[1] - v0.pos[1], v1.pos[2] - v0.pos[2] };
+	float edge2[3] = { v2.pos[0] - v0.pos[0], v2.pos[1] - v0.pos[1], v2.pos[2] - v0.pos[2] };
+
+	// 叉积计算法线
+	outNormal[0] = edge1[1] * edge2[2] - edge1[2] * edge2[1];
+	outNormal[1] = edge1[2] * edge2[0] - edge1[0] * edge2[2];
+	outNormal[2] = edge1[0] * edge2[1] - edge1[1] * edge2[0];
+
+	// 归一化
+	float length = std::sqrt(outNormal[0] * outNormal[0] +
+		outNormal[1] * outNormal[1] +
+		outNormal[2] * outNormal[2]);
+
+	if (length > 0.0f) {
+		outNormal[0] /= length;
+		outNormal[1] /= length;
+		outNormal[2] /= length;
+	}
+}
+
+// 计算所有顶点的法线
+void AppBase::calculateVertexNormals(std::vector<TextureLoadingVertexStructure>& obj_vertices,
+	const std::vector<uint32_t>& obj_indices)
+{
+	// 验证索引数量是3的倍数
+	if (obj_indices.size() % 3 != 0) {
+		return; // 或者抛出异常
+	}
+
+	// 为每个顶点创建法线累加器和计数
+	std::vector<std::array<float, 3>> normalSums(obj_vertices.size(), { 0.0f, 0.0f, 0.0f });
+	std::vector<int> normalCounts(obj_vertices.size(), 0);
+
+	// 遍历所有三角形
+	for (size_t i = 0; i < obj_indices.size(); i += 3) {
+		uint32_t idx0 = obj_indices[i];
+		uint32_t idx1 = obj_indices[i + 1];
+		uint32_t idx2 = obj_indices[i + 2];
+
+		// 验证索引有效性
+		if (idx0 >= obj_vertices.size() || idx1 >= obj_vertices.size() || idx2 >= obj_vertices.size()) {
+			continue;
+		}
+
+		// 获取三角形的三个顶点
+		const auto& v0 = obj_vertices[idx0];
+		const auto& v1 = obj_vertices[idx1];
+		const auto& v2 = obj_vertices[idx2];
+
+		// 计算面的法线
+		float faceNormal[3];
+		calculateFaceNormal(v0, v1, v2, faceNormal);
+
+		// 将面法线累加到每个顶点
+		for (int j = 0; j < 3; j++) {
+			normalSums[idx0][j] += faceNormal[j];
+			normalSums[idx1][j] += faceNormal[j];
+			normalSums[idx2][j] += faceNormal[j];
+		}
+
+		normalCounts[idx0]++;
+		normalCounts[idx1]++;
+		normalCounts[idx2]++;
+	}
+
+	// 计算每个顶点的平均法线并归一化
+	for (size_t i = 0; i < obj_vertices.size(); i++) {
+		if (normalCounts[i] > 0) {
+			// 计算平均值
+			float avgNormal[3] = {
+				normalSums[i][0] / normalCounts[i],
+				normalSums[i][1] / normalCounts[i],
+				normalSums[i][2] / normalCounts[i]
+			};
+
+			// 归一化
+			float length = std::sqrt(avgNormal[0] * avgNormal[0] +
+				avgNormal[1] * avgNormal[1] +
+				avgNormal[2] * avgNormal[2]);
+
+			if (length > 0.0f) {
+				obj_vertices[i].normal[0] = avgNormal[0] / length;
+				obj_vertices[i].normal[1] = avgNormal[1] / length;
+				obj_vertices[i].normal[2] = avgNormal[2] / length;
+			}
+			else {
+				// 如果法线长度为0，设置为默认值
+				obj_vertices[i].normal[0] = 0.0f;
+				obj_vertices[i].normal[1] = 1.0f;
+				obj_vertices[i].normal[2] = 0.0f;
+			}
+		}
+		else {
+			// 如果没有面使用这个顶点，设置默认法线
+			obj_vertices[i].normal[0] = 0.0f;
+			obj_vertices[i].normal[1] = 1.0f;
+			obj_vertices[i].normal[2] = 0.0f;
+		}
+	}
 }