Add bilinear filtering

include/engine.h

@@ -19,8 +19,7 @@ enum Engine_Input
     ROTATE_Z_POS,
     ROTATE_Z_NEG,
     SCALE_UP,
-    SCALE_DOWN,
+    SCALE_DOWN
-    SHADING_TOGGLE
 };
 
 

include/geometry.h

@@ -10,6 +10,7 @@
 // STRUCTURES
 struct Material
 {
+    bool smooth;
     ColorF32 kAmbient;
     ColorF32 kDiffuse;
 };
@@ -75,7 +76,6 @@ struct Mesh
     float scale;
 
     Material material;
-    bool smooth;
 
     Mesh_LocalData local;
     Mesh_TransformedData transformed;
@@ -88,8 +88,8 @@ void CullBackfaces(
         Point &camPosition);
 
 void RenderMesh(
-        Engine_Buffer &buffer, Mesh_TransformedData &mesh, bool smooth, Texture &texture,
+        Engine_Buffer &buffer, Mesh_TransformedData &mesh,
-        std::vector<TextureCoord> &uvs);
+        Texture &texture, std::vector<TextureCoord> &uvs);
 
 
 #define GEOMETRY_H

src/engine.cpp

@@ -35,6 +35,7 @@ int Engine_Init(Engine_Buffer &buffer, char *filename)
     mesh.position.z = 250;
     mesh.material.kDiffuse = {1.0,1.0,1.0,1.0};
     mesh.material.kAmbient = {1.0,1.0,1.0,1.0};
+    mesh.material.smooth = true;
 
     camera.SetFOV(90.0f, buffer.width, buffer.height);
 
@@ -53,8 +54,7 @@ void Engine_Render(Engine_Buffer &buffer, uint32_t input)
 
 
     // Clear the z-buffer
-    unsigned long bufferSize = (unsigned long)(buffer.width * buffer.height);
+    memset(buffer.zbuffer, 0, sizeof(float) * (size_t)(buffer.width * buffer.height));
-    memset(buffer.zbuffer, 0, bufferSize * sizeof(float));
 
 
     // Local space to world space
@@ -78,7 +78,7 @@ void Engine_Render(Engine_Buffer &buffer, uint32_t input)
 
 
     // Color the vertices for Gouraud shading
-    if (mesh.smooth)
+    if (mesh.material.smooth)
     {
         for (size_t f = 0; f < mesh.transformed.faces.size(); ++f)
         {
@@ -135,7 +135,7 @@ void Engine_Render(Engine_Buffer &buffer, uint32_t input)
         mesh.transformed.verts[v].point.z /= mesh.transformed.verts[v].point.w;
     }
 
-    RenderMesh(buffer, mesh.transformed, mesh.smooth, texture, mesh.local.uvs);
+    RenderMesh(buffer, mesh.transformed, texture, mesh.local.uvs);
 }
 
 void Engine_Shutdown(void)
@@ -208,13 +208,4 @@ static void CheckInputs(uint32_t input)
     {
         mesh.scale -= 0.1f;
     }
-
-    if (CHECK_BIT(input, SHADING_TOGGLE))
-    {
-        mesh.smooth = true;
-    }
-    else
-    {
-        mesh.smooth = false;
-    }
 }

src/geometry.cpp

@@ -66,8 +66,9 @@ void CullBackfaces(
 
 }
 
-void RenderMesh(Engine_Buffer &buffer, Mesh_TransformedData &mesh, bool smooth, Texture &texture,
+void RenderMesh(
-        std::vector<TextureCoord> &uvs)
+        Engine_Buffer &buffer, Mesh_TransformedData &mesh,
+        Texture &texture, std::vector<TextureCoord> &uvs)
 {
     for(size_t f = 0; f < mesh.faces.size(); ++f)
     {
@@ -138,37 +139,55 @@ void RenderMesh(Engine_Buffer &buffer, Mesh_TransformedData &mesh, bool smooth,
 
 
                     // Interpolate U and V
-                    float u = ((a * t0.u) + (b * t1.u) + (c * t2.u)) * abc;
+                    float uInterp = ((a * t0.u) + (b * t1.u) + (c * t2.u)) * abc;
-                    float v = ((a * t0.v) + (b * t1.v) + (c * t2.v)) * abc;
+                    float vInterp = ((a * t0.v) + (b * t1.v) + (c * t2.v)) * abc;
 
 
                     // Convert U and V to pixels in the texture image
-                    unsigned int uPixel = (unsigned int)(u * texture.width);
+                    uInterp *= texture.width;
-                    unsigned int vPixel = (unsigned int)(v * texture.height);
+                    vInterp *= texture.height;
+                    unsigned int u = (unsigned int)uInterp;
+                    unsigned int v = (unsigned int)vInterp;
 
 
-                    ColorF32 shading;
+                    // Gouraud shading
-
+                    ColorF32 shading =
-                    // Gouraud shading - interpolate color based on vertices
-                    if (smooth)
-                    {
-                        shading =
                         (barycenter[0] * v0.color)
                         + (barycenter[1] * v1.color)
                         + (barycenter[2] * v2.color);
-                    }
-                    // Flat shading - base color on single face color
-                    else
-                    {
-                        shading = mesh.faces[f].color;
-                    }
 
 
-                    // Shade the texel with lighting calculations
+                    // Bilinear filtering
-                    ColorU32 texel = texture.texels[vPixel][uPixel];
+                    float du = uInterp - u;
-                    texel.r *= shading.r;
+                    float dv = vInterp - v;
-                    texel.g *= shading.g;
+                    float duDiff = 1-du;
-                    texel.b *= shading.b;
+                    float dvDiff = 1-dv;
+
+                    ColorU32 color;
+
+                    color.b = (uint8_t)
+                        (duDiff * dvDiff * texture.texels[v][u].b
+                         + du * dvDiff * texture.texels[v][u+1].b
+                         + du * dv * texture.texels[v+1][u+1].b
+                         + duDiff * dv * texture.texels[v+1][u].b);
+
+                    color.g = (uint8_t)
+                        (duDiff * dvDiff * texture.texels[v][u].g
+                         + du * dvDiff * texture.texels[v][u+1].g
+                         + du * dv * texture.texels[v+1][u+1].g
+                         + duDiff * dv * texture.texels[v+1][u].g);
+
+                    color.r = (uint8_t)
+                        (duDiff * dvDiff * texture.texels[v][u].r
+                         + du * dvDiff * texture.texels[v][u+1].r
+                         + du * dv * texture.texels[v+1][u+1].r
+                         + duDiff * dv * texture.texels[v+1][u].r);
+
+
+                    // Shade the texture with the light calculations
+                    color.b *= shading.b;
+                    color.g *= shading.g;
+                    color.r *= shading.r;
 
 
                     // Interpolate 1/z for the z-buffer
@@ -179,12 +198,11 @@ void RenderMesh(Engine_Buffer &buffer, Mesh_TransformedData &mesh, bool smooth,
                         + (barycenter[2] * v2.point.w));
 
 
-
                     // Draw the pixel if it's closer than what's in the z-buffer
                     int pixel = (y * buffer.width + x);
                     if (zInv > buffer.zbuffer[pixel])
                     {
-                        DrawPixel(buffer.buffer, buffer.width, texel.u32, x, y);
+                        DrawPixel(buffer.buffer, buffer.width, color.u32, x, y);
 
                         buffer.zbuffer[pixel] = zInv;
                     }

src/platform.cpp

@@ -169,10 +169,6 @@ static void HandleEvent(
                 {
                     SET_BIT(platform.input, ROTATE_Y_NEG);
                 } break;
-                case SDLK_g:
-                {
-                    SET_BIT(platform.input, SHADING_TOGGLE);
-                } break;
                 case SDLK_UP:
                 {
                     SET_BIT(platform.input, SCALE_UP);
@@ -235,10 +231,6 @@ static void HandleEvent(
                 {
                     CLEAR_BIT(platform.input, ROTATE_Y_NEG);
                 } break;
-                case SDLK_g:
-                {
-                    CLEAR_BIT(platform.input, SHADING_TOGGLE);
-                } break;
                 case SDLK_UP:
                 {
                     CLEAR_BIT(platform.input, SCALE_UP);