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#include "Camera.hpp"
#include "Color.hpp"
#include "Engine.hpp"
#include "Geometry.hpp"
#include "Light.hpp"
#include "Loader.hpp"
#include "Matrix.hpp"
#include "Render.hpp"
#include "Transform.hpp"
#include "Vec.hpp"
#include <cstring>
#include <cstdio>
unsigned long constexpr CheckBit(uint32_t x, unsigned long bit)
{
return x & (1UL << bit);
}
static Mesh mesh;
static Camera camera;
static Light light;
static Matrix tPersp;
static Matrix tScreen;
static EngineMemory memory;
static void ComputeNormals();
static void CheckInputs(uint32_t input);
static void ClearDepthBuffer();
static void TransformToClipSpace();
static void ClipAndCull();
static void TransformToScreenSpace();
static void LightMesh();
int EngineInit(char* objFilename, char* mtlFilename)
{
int result;
result = ParseOBJ(objFilename, memory);
if (result < 0)
{
return -1;
}
result = ParseMTL(mtlFilename, memory);
if (result < 0)
{
return -1;
}
printf("Verts: %lu\n", memory.localVerts.size);
printf("Faces: %lu\n", memory.localFaces.size);
printf("Materials: %lu\n", memory.materials.size);
memory.transVerts.size = memory.localVerts.size;
// Compute vertex and face normals for lighting calculation
ComputeNormals();
// Mesh configuration
mesh.position.z = 200;
mesh.position.y = -100;
mesh.scale = 1.0f;
// Light configuration
light.position = Point(-300.0f, 200.0f, 0.0f);
light.color = ColorF32(1.0f, 1.0f, 1.0f, 1.0f);
light.intensity = 2.0f;
light.falloffConstant = 1.0f;
light.falloffLinear = 0.001f;
// Transformation matrices that do not change
tPersp = Transform_Perspective(camera);
tScreen = Transform_Screen(camera);
return 0;
}
void EngineRender(EngineBuffer& buffer, uint32_t input)
{
// Check for user input
CheckInputs(input);
// Clear the z-buffer
ClearDepthBuffer();
// Transform vertices to clip space
TransformToClipSpace();
// Clip near/far Z and cull backfaces
ClipAndCull();
// Light vertices and/or faces
LightMesh();
// Transform vertices to screen space
TransformToScreenSpace();
// Render
Render(buffer, memory);
}
void EngineShutdown()
{
}
// PRIVATE FUNCTIONS
static void CheckInputs(uint32_t input)
{
if (CheckBit(input, TRANSLATE_X_POS))
{
light.position.x += 10;
}
else if (CheckBit(input, TRANSLATE_X_NEG))
{
light.position.x -= 10;
}
if (CheckBit(input, TRANSLATE_Z_POS))
{
light.position.z += 10;
}
else if (CheckBit(input, TRANSLATE_Z_NEG))
{
light.position.z -= 10;
}
if (CheckBit(input, TRANSLATE_Y_POS))
{
light.position.y += 10;
}
else if (CheckBit(input, TRANSLATE_Y_NEG))
{
light.position.y -= 10;
}
if (CheckBit(input, ROTATE_X_POS))
{
mesh.rotation.x += 0.10f;
}
else if (CheckBit(input, ROTATE_X_NEG))
{
mesh.rotation.x -= 0.10f;
}
if (CheckBit(input, ROTATE_Y_POS))
{
mesh.rotation.y += 0.10f;
}
else if (CheckBit(input, ROTATE_Y_NEG))
{
mesh.rotation.y -= 0.10f;
}
if (CheckBit(input, ROTATE_Z_POS))
{
mesh.rotation.z += 0.10f;
}
else if (CheckBit(input, ROTATE_Z_NEG))
{
mesh.rotation.z -= 0.10f;
}
if (CheckBit(input, SCALE_UP))
{
light.color.b = 0.0f;
light.color.g = 0.0f;
light.color.r = 1.0f;
}
else if (CheckBit(input, SCALE_DOWN))
{
light.color.b = 1.0f;
light.color.g = 1.0f;
light.color.r = 1.0f;
}
}
static void ComputeNormals()
{
VertexList& verts = memory.localVerts;
FaceList& faces = memory.localFaces;
int vertexNormalCount[VERTEX_LIMIT] = {};
for (size_t f = 0; f < faces.size; ++f)
{
Face& face = faces.data[f];
Vertex& vert0 = verts.data[face.vertIndex[0]];
Vertex& vert1 = verts.data[face.vertIndex[1]];
Vertex& vert2 = verts.data[face.vertIndex[2]];
Vector v01 = vert1.position - vert0.position;
Vector v02 = vert2.position - vert0.position;
Vector normal = Vector::Cross(v01, v02);
// Add each vertex's normal to the sum for future averaging
vert0.normal += normal;
vert1.normal += normal;
vert2.normal += normal;
++vertexNormalCount[face.vertIndex[0]];
++vertexNormalCount[face.vertIndex[1]];
++vertexNormalCount[face.vertIndex[2]];
}
for (size_t v = 0; v < verts.size; ++v)
{
if (vertexNormalCount[v] > 0)
{
// Compute the average normal for this vertex
verts.data[v].normal /= static_cast<float>(vertexNormalCount[v]);
verts.data[v].normal.Normalize();
}
}
}
static void ClearDepthBuffer()
{
memset(memory.zbuffer, 0, sizeof(memory.zbuffer));
}
static void TransformToClipSpace()
{
VertexList& localVerts = memory.localVerts;
VertexList& transVerts = memory.transVerts;
Matrix tTranslate = Transform_Translate(mesh.position);
Matrix tRotate = Transform_Rotate(mesh.rotation);
Matrix tScale = Transform_Scale(mesh.scale);
Matrix tView = Transform_View(camera);
for (size_t v = 0; v < localVerts.size; ++v)
{
transVerts.data[v].position =
localVerts.data[v].position * tScale * tRotate * tTranslate * tView * tPersp;
transVerts.data[v].normal =
localVerts.data[v].normal * tScale * tRotate * tTranslate;
}
}
void ClipAndCull()
{
FaceList& localFaces = memory.localFaces;
FaceList& transFaces = memory.transFaces;
VertexList& verts = memory.transVerts;
int faceIndex = 0;
for (size_t f = 0; f < localFaces.size; ++f)
{
Face& face = localFaces.data[f];
Point& p0 = verts.data[face.vertIndex[0]].position;
Point& p1 = verts.data[face.vertIndex[1]].position;
Point& p2 = verts.data[face.vertIndex[2]].position;
// Ignore this face if its Z is outside the Z clip planes
if ((p0.z < -p0.w)
|| (p0.z > p0.w)
|| (p1.z < -p1.w)
|| (p1.z > p1.w)
|| (p2.z < -p2.w)
|| (p2.z > p2.w))
{
continue;
}
// Calculate the face's normal (inverted for Blender-compatibility)
Vector v01 = p1 - p0;
Vector v02 = p2 - p0;
Vector normal = -Vector::Cross(v01, v02);
// Eye vector to viewport
Vector view = camera.position - p0;
float dot = Vector::Dot(normal, view);
// Not a backface; add it to the list
if (dot < 0.0f)
{
transFaces.data[faceIndex] = face;
++faceIndex;
transFaces.size = (size_t)faceIndex;
}
}
}
static void TransformToScreenSpace()
{
VertexList& verts = memory.transVerts;
for (size_t v = 0; v < verts.size; ++v)
{
verts.data[v].position *= tScreen;
verts.data[v].position.x /= verts.data[v].position.w;
verts.data[v].position.y /= verts.data[v].position.w;
verts.data[v].position.z /= verts.data[v].position.w;
}
}
static void LightMesh()
{
VertexList& verts = memory.transVerts;
FaceList& faces = memory.transFaces;
MaterialList& materials = memory.materials;
for (size_t f = 0; f < faces.size; ++f)
{
Face& face = faces.data[f];
Material& material = materials.data[face.materialIndex];
// Gouraud shading
for (auto index : face.vertIndex)
{
Vertex& vert = verts.data[index];
vert.color = light.Compute(vert.position, vert.normal, material, camera);
}
}
}