yunusemregul / bsp_viewer Goto Github PK

void generatePatch(const std::vector<glm::vec3>& inVertices, const std::vector<unsigned int>& inIndices, std::vector<glm::vec3>& outVertices, std::vector<glm::vec2>& uvs, std::vector<unsigned int>& indices, ddispinfo_t dispInfo, float tv[2][4], dface_t face) {

		auto lerp = [](glm::vec3 a, glm::vec3 b, float t) -> glm::vec3 {
			return a + t * (b - a);
		};

		std::vector<glm::vec3> v = { inVertices[0], inVertices[1], inVertices[2], inVertices[3] };

		//check which corner has the minimum value, to use it as starting point
		float startDist = 10000000000000; //big number, nothing special
		int startIndex = -1;
		for (int j = 0; j < 4; j++) {
			const float dist = glm::distance(v[j], dispInfo.startPosition);
			if (dist < startDist) {
				startIndex = j;
				startDist = dist;
			}
		}

		//rotate the vector to put the lowest point first
		if (startIndex != 0)
			std::rotate(v.begin(), v.begin() + startIndex, v.end());
		

		int power = dispInfo.power;
		int numVerts = glm::pow((glm::pow(2, power) + 1), 2);
		int length = (1 << power) + 1;

		outVertices.resize(numVerts);

		glm::vec3 v0{};
		glm::vec3 v1{};

		for (int i = 0; i < length; i++) {
			const float ty = (float)i / (float)(length - 1);
			v0 = lerp(v[0], v[1], ty);
			v1 = lerp(v[3], v[2], ty);

			for (int j = 0; j < length; j++) {
				int index = dispInfo.DispVertStart + (i * length) + j;

				auto& dispVertex = m_pBspFileData.vertDisps[index];

				const float tx = (float)j / (float)(length - 1.0f);
				glm::vec3 vtx = lerp(v0, v1, tx);
                                
                                //Generate texcoords
				float u = (tv[0][0] * vtx.x) + (tv[0][1] * vtx.y) + (tv[0][2] * vtx.z) + tv[0][3];
				float v = (tv[1][0] * vtx.x) + (tv[1][1] * vtx.y) + (tv[1][2] * vtx.z) + tv[1][3];
				uvs.push_back(glm::vec2(u, v));

				//displace
				vtx += dispVertex.vec * dispVertex.dist;

				outVertices[i * length + j] = vtx;
			}
		}

		//Triangulate
		int edge = 0;
		for (int i = 0; i < numVerts - length; i++) {
			if (edge == length - 1) {
				edge = 0;
				continue;
			}

			indices.push_back(i + 1);
			indices.push_back(i);
			indices.push_back(i + length);

			indices.push_back(i + 1);
			indices.push_back(i + length);
			indices.push_back(i + length + 1);

			edge++;
		}
	}