345 lines
7.5 KiB
C++
345 lines
7.5 KiB
C++
#include "camera.h"
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#include "color.h"
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#include "engine.h"
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#include "geometry.h"
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#include "light.h"
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#include "loader.h"
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#include "matrix.h"
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#include "render.h"
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#include "transform.h"
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#include "util.h"
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#include "vec.h"
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#include <cstring>
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#include <cstdio>
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// GLOBALS
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static Mesh mesh;
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static Camera camera;
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static Light light;
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static Matrix tPersp;
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static Matrix tScreen;
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static EngineMemory memory;
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// PRIVATE PROTOTYPES
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static void ComputeNormals(void);
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static void CheckInputs(uint32_t input);
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static void ClearDepthBuffer(void);
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static void TransformToClipSpace(void);
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static void ClipAndCull(void);
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static void TransformToScreenSpace(void);
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static void LightMesh(void);
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// PUBLIC FUNCTIONS
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int EngineInit(char *objFilename, char *mtlFilename)
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{
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int result;
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result = ParseOBJ(objFilename, memory);
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if (result < 0)
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{
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return -1;
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}
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result = ParseMTL(mtlFilename, memory);
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if (result < 0)
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{
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return -1;
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}
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printf("Verts: %lu\n", memory.localVerts.size);
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printf("Faces: %lu\n", memory.localFaces.size);
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printf("Materials: %lu\n", memory.materials.size);
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memory.transVerts.size = memory.localVerts.size;
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// Compute vertex and face normals for lighting calculation
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ComputeNormals();
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// Mesh configuration
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mesh.position.z = 125;
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mesh.position.y = -125;
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mesh.scale = 1.0f;
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// Light configuration
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light.position = Point(-100.0f, 200.0f, 0.0f);
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light.color = {1.0f, 1.0f, 1.0f, 1.0f};
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light.intensity = 2.0f;
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light.falloffConstant = 1.0f;
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light.falloffLinear = 0.001f;
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// Transformation matrices that do not change
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tPersp = Transform_Perspective(camera);
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tScreen = Transform_Screen(camera);
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return 0;
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}
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void EngineRender(EngineBuffer &buffer, uint32_t input)
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{
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// Check for user input
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CheckInputs(input);
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// Clear the z-buffer
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ClearDepthBuffer();
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// Transform vertices to clip space
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TransformToClipSpace();
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// Clip near/far Z and cull backfaces
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ClipAndCull();
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// Light vertices and/or faces
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LightMesh();
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// Transform vertices to screen space
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TransformToScreenSpace();
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// Render
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Render(buffer, memory);
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}
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void EngineShutdown(void)
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{
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}
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// PRIVATE FUNCTIONS
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static void CheckInputs(uint32_t input)
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{
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if (CHECK_BIT(input, TRANSLATE_X_POS))
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{
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light.position.x += 10;
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}
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else if (CHECK_BIT(input, TRANSLATE_X_NEG))
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{
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light.position.x -= 10;
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}
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if (CHECK_BIT(input, TRANSLATE_Z_POS))
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{
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light.position.z += 10;
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}
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else if (CHECK_BIT(input, TRANSLATE_Z_NEG))
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{
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light.position.z -= 10;
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}
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if (CHECK_BIT(input, TRANSLATE_Y_POS))
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{
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light.position.y += 10;
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}
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else if (CHECK_BIT(input, TRANSLATE_Y_NEG))
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{
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light.position.y -= 10;
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}
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if (CHECK_BIT(input, ROTATE_X_POS))
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{
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mesh.rotation.x += .10;
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}
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else if (CHECK_BIT(input, ROTATE_X_NEG))
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{
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mesh.rotation.x -= .10;
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}
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if (CHECK_BIT(input, ROTATE_Y_POS))
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{
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mesh.rotation.y += .10;
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}
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else if (CHECK_BIT(input, ROTATE_Y_NEG))
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{
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mesh.rotation.y -= .10;
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}
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if (CHECK_BIT(input, ROTATE_Z_POS))
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{
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mesh.rotation.z += .10;
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}
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else if (CHECK_BIT(input, ROTATE_Z_NEG))
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{
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mesh.rotation.z -= .10;
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}
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if (CHECK_BIT(input, SCALE_UP))
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{
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light.color.b = 0.0f;
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light.color.g = 0.0f;
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light.color.r = 1.0f;
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}
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else if (CHECK_BIT(input, SCALE_DOWN))
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{
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light.color.b = 1.0f;
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light.color.g = 1.0f;
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light.color.r = 1.0f;
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}
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}
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static void ComputeNormals(void)
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{
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VertexList &verts = memory.localVerts;
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FaceList &faces = memory.localFaces;
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int vertexNormalCount[VERTEX_LIMIT] = {};
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for (size_t f = 0; f < faces.size; ++f)
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{
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Face &face = faces.data[f];
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Vertex &vert0 = verts.data[face.vertIndex[0]];
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Vertex &vert1 = verts.data[face.vertIndex[1]];
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Vertex &vert2 = verts.data[face.vertIndex[2]];
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Vector v01 = vert1.point - vert0.point;
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Vector v02 = vert2.point - vert0.point;
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Vector normal = VectorCross(v01, v02);
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// Add each vertex's normal to the sum for future averaging
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vert0.normal += normal;
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vert1.normal += normal;
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vert2.normal += normal;
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++vertexNormalCount[face.vertIndex[0]];
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++vertexNormalCount[face.vertIndex[1]];
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++vertexNormalCount[face.vertIndex[2]];
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}
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for (size_t v = 0; v < verts.size; ++v)
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{
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if (vertexNormalCount[v] > 0)
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{
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// Compute the average normal for this vertex
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verts.data[v].normal /= vertexNormalCount[v];
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VectorNormalize(verts.data[v].normal);
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}
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}
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}
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static void ClearDepthBuffer(void)
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{
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memset(memory.zbuffer, 0, sizeof(memory.zbuffer));
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}
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static void TransformToClipSpace(void)
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{
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VertexList &localVerts = memory.localVerts;
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VertexList &transVerts = memory.transVerts;
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Matrix tTranslate = Transform_Translate(mesh.position);
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Matrix tRotate = Transform_Rotate(mesh.rotation);
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Matrix tScale = Transform_Scale(mesh.scale);
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Matrix tView = Transform_View(camera);
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for (size_t v = 0; v < localVerts.size; ++v)
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{
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transVerts.data[v].point =
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localVerts.data[v].point * tScale * tRotate * tTranslate * tView * tPersp;
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transVerts.data[v].normal =
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localVerts.data[v].normal * tScale * tRotate * tTranslate;
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}
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}
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void ClipAndCull(void)
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{
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FaceList &localFaces = memory.localFaces;
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FaceList &transFaces = memory.transFaces;
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VertexList &verts = memory.transVerts;
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int faceIndex = 0;
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for (size_t f = 0; f < localFaces.size; ++f)
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{
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Face &face = localFaces.data[f];
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Point &p0 = verts.data[face.vertIndex[0]].point;
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Point &p1 = verts.data[face.vertIndex[1]].point;
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Point &p2 = verts.data[face.vertIndex[2]].point;
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// Ignore this face if its Z is outside the Z clip planes
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if ( (p0.z < -p0.w)
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|| (p0.z > p0.w)
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|| (p1.z < -p1.w)
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|| (p1.z > p1.w)
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|| (p2.z < -p2.w)
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|| (p2.z > p2.w))
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{
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continue;
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}
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// Calculate the face's normal (inverted for Blender-compatibility)
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Vector v01 = p1 - p0;
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Vector v02 = p2 - p0;
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Vector normal = -VectorCross(v01, v02);
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// Eye vector to viewport
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Vector view = camera.position - p0;
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float dot = VectorDot(normal, view);
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// Not a backface; add it to the list
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if (dot < EPSILON_E3)
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{
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transFaces.data[faceIndex] = face;
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++faceIndex;
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transFaces.size = (size_t)faceIndex;
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}
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}
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}
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static void TransformToScreenSpace(void)
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{
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VertexList &verts = memory.transVerts;
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for (size_t v = 0; v < verts.size; ++v)
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{
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verts.data[v].point *= tScreen;
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verts.data[v].point.x /= verts.data[v].point.w;
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verts.data[v].point.y /= verts.data[v].point.w;
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verts.data[v].point.z /= verts.data[v].point.w;
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}
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}
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static void LightMesh(void)
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{
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VertexList &verts = memory.transVerts;
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FaceList &faces = memory.transFaces;
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MaterialList &materials = memory.materials;
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for (size_t f = 0; f < faces.size; ++f)
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{
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Face &face = faces.data[f];
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Material &material = materials.data[face.materialIndex];
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// Gouraud shading
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for (int i = 0; i < 3; ++i)
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{
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Vertex &vert = verts.data[face.vertIndex[i]];
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vert.color = ComputeLight(vert, material, light);
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}
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}
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}
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