diff options
Diffstat (limited to 'src/models.c')
| -rw-r--r-- | src/models.c | 95 |
1 files changed, 88 insertions, 7 deletions
diff --git a/src/models.c b/src/models.c index 4793ee0a..afeee0fc 100644 --- a/src/models.c +++ b/src/models.c @@ -36,9 +36,8 @@ * **********************************************************************************************/ -#include "config.h" - -#include "raylib.h" +#include "config.h" // Defines module configuration flags +#include "raylib.h" // Declares module functions #include "utils.h" // Required for: fopen() Android mapping @@ -2119,16 +2118,98 @@ BoundingBox MeshBoundingBox(Mesh mesh) return box; } -// Compute mesh tangents +// Compute mesh tangents +// NOTE: To calculate mesh tangents and binormals we need mesh vertex positions and texture coordinates +// Implementation base don: https://answers.unity.com/questions/7789/calculating-tangents-vector4.html void MeshTangents(Mesh *mesh) { - // TODO: Compute mesh tangents + if (mesh->tangents == NULL) mesh->tangents = (float *)malloc(mesh->vertexCount*4*sizeof(float)); + else TraceLog(LOG_WARNING, "Mesh tangents already exist"); + + Vector3 *tan1 = (Vector3 *)malloc(mesh->vertexCount*sizeof(Vector3)); + Vector3 *tan2 = (Vector3 *)malloc(mesh->vertexCount*sizeof(Vector3)); + + for (int i = 0; i < mesh->vertexCount; i += 3) + { + // Get triangle vertices + Vector3 v1 = { mesh->vertices[(i + 0)*3 + 0], mesh->vertices[(i + 0)*3 + 1], mesh->vertices[(i + 0)*3 + 2] }; + Vector3 v2 = { mesh->vertices[(i + 1)*3 + 0], mesh->vertices[(i + 1)*3 + 1], mesh->vertices[(i + 1)*3 + 2] }; + Vector3 v3 = { mesh->vertices[(i + 2)*3 + 0], mesh->vertices[(i + 2)*3 + 1], mesh->vertices[(i + 2)*3 + 2] }; + + // Get triangle texcoords + Vector2 uv1 = { mesh->texcoords[(i + 0)*2 + 0], mesh->texcoords[(i + 0)*2 + 1] }; + Vector2 uv2 = { mesh->texcoords[(i + 1)*2 + 0], mesh->texcoords[(i + 1)*2 + 1] }; + Vector2 uv3 = { mesh->texcoords[(i + 2)*2 + 0], mesh->texcoords[(i + 2)*2 + 1] }; + + float x1 = v2.x - v1.x; + float y1 = v2.y - v1.y; + float z1 = v2.z - v1.z; + float x2 = v3.x - v1.x; + float y2 = v3.y - v1.y; + float z2 = v3.z - v1.z; + + float s1 = uv2.x - uv1.x; + float t1 = uv2.y - uv1.y; + float s2 = uv3.x - uv1.x; + float t2 = uv3.y - uv1.y; + + float div = s1*t2 - s2*t1; + float r = (div == 0.0f) ? 0.0f : 1.0f/div; + + Vector3 sdir = { (t2*x1 - t1*x2)*r, (t2*y1 - t1*y2)*r, (t2*z1 - t1*z2)*r }; + Vector3 tdir = { (s1*x2 - s2*x1)*r, (s1*y2 - s2*y1)*r, (s1*z2 - s2*z1)*r }; + + tan1[i + 0] = sdir; + tan1[i + 1] = sdir; + tan1[i + 2] = sdir; + + tan2[i + 0] = tdir; + tan2[i + 1] = tdir; + tan2[i + 2] = tdir; + } + + // Compute tangents considering normals + for (int i = 0; i < mesh->vertexCount; ++i) + { + Vector3 normal = { mesh->normals[i*3 + 0], mesh->normals[i*3 + 1], mesh->normals[i*3 + 2] }; + Vector3 tangent = tan1[i]; + + // TODO: Review, not sure if tangent computation is right, just used reference proposed maths... + #if defined(COMPUTE_TANGENTS_METHOD_01) + Vector3 tmp = Vector3Subtract(tangent, Vector3Multiply(normal, Vector3DotProduct(normal, tangent))); + tmp = Vector3Normalize(tmp); + mesh->tangents[i*4 + 0] = tmp.x; + mesh->tangents[i*4 + 1] = tmp.y; + mesh->tangents[i*4 + 2] = tmp.z; + mesh->tangents[i*4 + 3] = 1.0f; + #else + Vector3OrthoNormalize(&normal, &tangent); + mesh->tangents[i*4 + 0] = tangent.x; + mesh->tangents[i*4 + 1] = tangent.y; + mesh->tangents[i*4 + 2] = tangent.z; + mesh->tangents[i*4 + 3] = (Vector3DotProduct(Vector3CrossProduct(normal, tangent), tan2[i]) < 0.0f) ? -1.0f : 1.0f; + #endif + } + + free(tan1); + free(tan2); + + TraceLog(LOG_INFO, "Tangents computed for mesh"); } -// Compute mesh binormals +// Compute mesh binormals (aka bitangent) void MeshBinormals(Mesh *mesh) { - // TODO: Compute mesh binormals + for (int i = 0; i < mesh->vertexCount; i++) + { + Vector3 normal = { mesh->normals[i*3 + 0], mesh->normals[i*3 + 1], mesh->normals[i*3 + 2] }; + Vector3 tangent = { mesh->tangents[i*4 + 0], mesh->tangents[i*4 + 1], mesh->tangents[i*4 + 2] }; + float tangentW = mesh->tangents[i*4 + 3]; + + Vector3 binormal = Vector3Multiply(Vector3CrossProduct(normal, tangent), tangentW); + + // TODO: Register computed binormal in mesh->binormal ? + } } //---------------------------------------------------------------------------------- |