various improvements

- cleaned up the computation of the camera's matrix
- changed VertexData to being a struct which transmit data between the "vertex shader" and the "fragment shader"
- started working on keyboard and mouse controls
- added fov (field of view)
- changed quaternion to euler angles conversion, from zyx to zxy
- fixed computations of z coordinates in triangle rendering
- improved naming in the triangle rasterizer

5 files changed, 38 insertions, 28 deletions

diff --git a/src/o3d/camera.h b/src/o3d/camera.h
index 27c31eb..832f473 100644
--- a/src/o3d/camera.h
+++ b/src/o3d/camera.h
@@ -1,12 +1,22 @@
 #ifndef O3D_CAMERA_H
 #define O3D_CAMERA_H
 
+#include "math/mat4.h"
 #include "math/tform.h"
 
+using
+    engine::math::Matrix4,
+    engine::math::Transform;
+
 namespace engine::o3d {
 
 struct Camera {
-    engine::math::Transform transform;
+    float fov;
+    Transform transform;
+
+    constexpr Matrix4 to_mat4(float aspect_ratio, float min_z, float max_z) const & {
+        return Matrix4::projection(fov, aspect_ratio, min_z, max_z) * transform.to_inverse_mat4();
+    }
 };
 
 }
diff --git a/src/o3d/mesh.cpp b/src/o3d/mesh.cpp
index 60c7f8b..2423e88 100644
--- a/src/o3d/mesh.cpp
+++ b/src/o3d/mesh.cpp
@@ -6,26 +6,25 @@
 
 using namespace engine::o3d;
 
-Mesh Mesh::plane() {
+Mesh Mesh::plane(float width, float height) {
+    const float w2 = width / 2,
+                h2 = height / 2;
     return {
         {
-            {-1.f, 0.f, -1.f, 1.f},
-            {+1.f, 0.f, -1.f, 1.f},
-            {+1.f, 0.f, +1.f, 1.f},
-            {-1.f, 0.f, +1.f, 1.f},
+            {-w2 / 2, 0.f, -h2 / 2, 1.f},
+            {+w2 / 2, 0.f, -h2 / 2, 1.f},
+            {+w2 / 2, 0.f, +h2 / 2, 1.f},
+            {-w2 / 2, 0.f, +h2 / 2, 1.f},
         },
-        { {0.f, 0.f, -1.f} },
         {
-            {0.f, 0.f},
-            {1.f, 0.f},
-            {1.f, 1.f},
-            {0.f, 1.f},
+            {0.f, -1.f, 0.f},
+            {0.f, +1.f, 0.f},
         },
         {
-            {{ {{0, 0, 0}}, {{1, 0, 1}}, {{2, 0, 2}} }},
-            {{ {{2, 0, 2}}, {{3, 0, 3}}, {{0, 0, 0}} }},
-            {{ {{0, 0, 0}}, {{3, 0, 3}}, {{2, 0, 2}} }},
-            {{ {{2, 0, 2}}, {{1, 0, 1}}, {{0, 0, 0}} }},
+            {{ {{0, 0}}, {{1, 0}}, {{2, 0}} }},
+            {{ {{2, 0}}, {{3, 0}}, {{0, 0}} }},
+            {{ {{0, 1}}, {{3, 1}}, {{2, 1}} }},
+            {{ {{2, 1}}, {{1, 1}}, {{0, 1}} }},
         }
     };
 }
diff --git a/src/o3d/mesh.h b/src/o3d/mesh.h
index 1c70ca4..acc48b5 100644
--- a/src/o3d/mesh.h
+++ b/src/o3d/mesh.h
@@ -6,19 +6,17 @@
 #include <iterator>
 #include <cstddef>
 #include "math/vector.h"
-#include "o3d/vertex_data.h"
 
 namespace engine::o3d {
 
 using engine::math::Vector3, engine::math::Vector4;
 
 struct Mesh {
-    static Mesh plane();
+    static Mesh plane(float width, float height);
 
     std::vector<Vector4> vertices;
     std::vector<Vector3> normals;
-    std::vector<VertexData> vertices_data;
-    std::vector<std::array<std::array<std::size_t, 3>, 3>> indices;
+    std::vector<std::array<std::array<std::size_t, 2>, 3>> indices;
 };
 
 }
diff --git a/src/o3d/tri_deriv.cpp b/src/o3d/tri_deriv.cpp
index b4184bc..a22067e 100644
--- a/src/o3d/tri_deriv.cpp
+++ b/src/o3d/tri_deriv.cpp
@@ -51,7 +51,7 @@ static void _perspective_crop_x(std::vector<TriangleDerived>& tris, TriangleDeri
                 {
                     x,
                     q2->vertex.y + fac2 * dq2.y,
-                    fac2_b * q1->vertex.z + (1.f - fac2_b) * q2->vertex.z,
+                    (fac2_b * q1->vertex.w * q1->vertex.z + (1.f - fac2_b) * q2->vertex.w * q2->vertex.z) / r2w,
                     r2w
                 },
                 fac2_b * q1->b0 + (1.f - fac2_b) * q2->b0,
@@ -65,7 +65,7 @@ static void _perspective_crop_x(std::vector<TriangleDerived>& tris, TriangleDeri
                 {
                     x,
                     q3->vertex.y + fac3 * dq3.y,
-                    fac3_b * q1->vertex.z + (1.f - fac3_b) * q3->vertex.z,
+                    (fac3_b * q1->vertex.w * q1->vertex.z + (1.f - fac3_b) * q3->vertex.w * q3->vertex.z) / r3w,
                     r3w
                 },
                 fac3_b * q1->b0 + (1.f - fac3_b) * q3->b0,
@@ -144,7 +144,7 @@ static void _perspective_crop_y(std::vector<TriangleDerived>& tris, TriangleDeri
                 {
                     q2->vertex.x + fac2 * dq2.x,
                     y,
-                    fac2_b * q1->vertex.z + (1.f - fac2_b) * q2->vertex.z,
+                    (fac2_b * q1->vertex.w * q1->vertex.z + (1.f - fac2_b) * q2->vertex.w * q2->vertex.z) / r2w,
                     r2w
                 },
                 fac2_b * q1->b0 + (1.f - fac2_b) * q2->b0,
@@ -158,7 +158,7 @@ static void _perspective_crop_y(std::vector<TriangleDerived>& tris, TriangleDeri
                 {
                     q3->vertex.x + fac3 * dq3.x,
                     y,
-                    fac3_b * q1->vertex.z + (1.f - fac3_b) * q3->vertex.z,
+                    (fac3_b * q1->vertex.w * q1->vertex.z + (1.f - fac3_b) * q3->vertex.w * q3->vertex.z) / r3w,
                     r3w
                 },
                 fac3_b * q1->b0 + (1.f - fac3_b) * q3->b0,
diff --git a/src/o3d/vertex_data.h b/src/o3d/vertex_data.h
index 71f42cd..22fa76b 100644
--- a/src/o3d/vertex_data.h
+++ b/src/o3d/vertex_data.h
@@ -1,24 +1,27 @@
 #ifndef O3D_VERTEX_DATA_H
 #define O3D_VERTEX_DATA_H
 
+#include "math/vector.h"
+
+using
+    engine::math::Vector3;
+
 namespace engine::o3d {
 
 struct VertexData {
     static constexpr VertexData lerp(const VertexData& vd1, const VertexData& vd2, float b0) {
         return {
-            b0 * vd1.tx + (1.f - b0) * vd2.tx,
-            b0 * vd1.ty + (1.f - b0) * vd2.ty
+            b0 * vd1.world_loc + (1.f - b0) * vd2.world_loc,
         };
     }
 
     static constexpr VertexData bilerp(const VertexData& vd1, const VertexData& vd2, const VertexData& vd3, float b0, float b1) {
         return {
-            b0 * vd1.tx + b1 * vd2.tx + (1.f - b0 - b1) * vd3.tx,
-            b0 * vd1.ty + b1 * vd2.ty + (1.f - b0 - b1) * vd3.ty
+            b0 * vd1.world_loc + b1 * vd2.world_loc + (1.f - b0 - b1) * vd3.world_loc,
         };
     }
 
-    float tx, ty;
+    Vector3 world_loc;
 };
 
 }