Changeset: 26 Make SimpleGeometryObject render a cube

1 files changed, 88 insertions, 19 deletions

diff --git a/source/SceneThings.cpp b/source/SceneThings.cpp
index 5dcec1a..6e4624b 100644
--- a/source/SceneThings.cpp
+++ b/source/SceneThings.cpp
@@ -8,40 +8,109 @@
 SimpleGeometryObject::SimpleGeometryObject(GameWorld* world)
 	: GameObject(KD_SimpleGeometry, world)
 	, mRenderObject()
-	, mSize{ 100.0f, 100.0f }
-	, mColor(60, 60, 60) {
+	, mSize{ 50.0f, 50.0f, 50 }
+	, mXFaceColor(kXAxisColor)
+	, mYFaceColor(kYAxisColor)
+	, mZFaceColor(kZAxisColor)
+	, mNeedsRebuildMesh{ true } {
 	mRenderObject.SetMaterial(gDefaultMaterial.Get());
 	mRenderObject.SetFormat(gVformatStandard.Get(), Tags::IT_16Bit);
 	mRenderObject.RebuildIfNecessary();
-	UpdateRenderObject();
 }
 
-void SimpleGeometryObject::SetSize(glm::vec2 size) {
+void SimpleGeometryObject::SetSize(glm::vec3 size) {
 	mSize = size;
-	UpdateRenderObject();
+	mNeedsRebuildMesh = true;
 }
 
-void SimpleGeometryObject::SetColor(RgbaColor color) {
-	mColor = color;
-	UpdateRenderObject();
+void SimpleGeometryObject::SetXFaceColor(RgbaColor color) {
+	mXFaceColor = color;
+	mNeedsRebuildMesh = true;
 }
 
-std::span<const RenderObject> SimpleGeometryObject::GetRenderObjects() const {
-	return { &mRenderObject, 1 };
+void SimpleGeometryObject::SetYFaceColor(RgbaColor color) {
+	mYFaceColor = color;
+	mNeedsRebuildMesh = true;
+}
+
+void SimpleGeometryObject::SetZFaceColor(RgbaColor color) {
+	mZFaceColor = color;
+	mNeedsRebuildMesh = true;
 }
 
-void SimpleGeometryObject::UpdateRenderObject() {
+std::span<const RenderObject> SimpleGeometryObject::GetRenderObjects() const {
 	using namespace Tags;
 
-	uint16_t indices[6];
-	Index_U16::Assign(indices, 0);
-	mRenderObject.GetIndexBuffer()->Upload((const std::byte*)indices, IT_16Bit, std::size(indices));
+	if (mNeedsRebuildMesh) {
+		mNeedsRebuildMesh = false;
+
+		Vertex_PTC vertices[4 /*vertices per face*/ * 6 /*faces*/];
+		uint16_t indices[3 /*indices per triangle*/ * 2 /*triangles per face*/ * 6 /*faces*/];
+
+		auto pos = GetPos();
+		auto extents = mSize / 2.0f;
 
-	Vertex_PTC vertices[4];
-	Vertex_PTC::Assign(vertices, Rect<float>{ -mSize / 2.0f, mSize });
-	Vertex_PTC::Assign(vertices, 0.0f);
-	Vertex_PTC::Assign(vertices, mColor);
-	mRenderObject.GetVertexBufferBindings().bindings[0]->Upload((const std::byte*)vertices, sizeof(vertices));
+		int faceGenVerticesIdx = 0;
+		int faceGenIndicesIdx = 0;
+		auto GenerateFace = [&](glm::vec3 faceCenter, glm::vec3 firstExtentVec, glm::vec3 secondExtentVec, RgbaColor color) {
+			// Generates (if viewing top down on the face): bottom left, top left, bottom right, top right
+			//                                              (-1, -1)   , (-1, 1) , (1, -1)     , (1, 1)
+			//                                              idx=0      , idx=1   , idx=2       , idx=3
+
+			// These are index offsets, see above comment
+			constexpr int kBottomLeft = 0;
+			constexpr int kTopLeft = 1;
+			constexpr int kBottomRight = 2;
+			constexpr int kTopRight = 3;
+
+			int startVertIdx = faceGenVerticesIdx;
+			for (float firstDir : { -1, 1 }) {
+				for (float secondDir : { -1, 1 }) {
+					auto vertPos = faceCenter + firstExtentVec * firstDir + secondExtentVec * secondDir;
+					auto& vert = vertices[faceGenVerticesIdx];
+					vert.x = vertPos.x;
+					vert.y = vertPos.y;
+					vert.z = vertPos.z;
+					vert.r = color.r;
+					vert.g = color.g;
+					vert.b = color.b;
+					vert.a = color.a;
+					faceGenVerticesIdx += 1;
+				}
+			}
+
+			// Triangle #1
+			indices[faceGenIndicesIdx++] = startVertIdx + kTopRight;
+			indices[faceGenIndicesIdx++] = startVertIdx + kTopLeft;
+			indices[faceGenIndicesIdx++] = startVertIdx + kBottomLeft;
+			// Triangle #2
+			indices[faceGenIndicesIdx++] = startVertIdx + kTopRight;
+			indices[faceGenIndicesIdx++] = startVertIdx + kBottomLeft;
+			indices[faceGenIndicesIdx++] = startVertIdx + kBottomRight;
+		};
+		for (int xDir : { -1, 1 }) {
+			float x = pos.x + xDir * extents.x;
+			GenerateFace(glm::vec3(x, pos.y, pos.z), glm::vec3(0, 0, extents.z), glm::vec3(0, extents.y, 0), mXFaceColor);
+		}
+		for (int yDir : { -1, 1 }) {
+			float y = pos.y + yDir * extents.y;
+			GenerateFace(glm::vec3(pos.x, y, pos.z), glm::vec3(extents.x, 0, 0), glm::vec3(0, 0, extents.z), mYFaceColor);
+		}
+		for (int zDir : { -1, 1 }) {
+			float z = pos.z + zDir * extents.z;
+			GenerateFace(glm::vec3(pos.x, pos.y, z), glm::vec3(extents.x, 0, 0), glm::vec3(0, extents.y, 0), mZFaceColor);
+		}
+
+		for (auto& vert : vertices) {
+			vert.u = 0.0f;
+			vert.v = 0.0f;
+		}
+
+		mRenderObject.GetVertexBufferBindings().bindings[0]->Upload((const std::byte*)vertices, sizeof(vertices));
+		mRenderObject.GetIndexBuffer()->Upload((const std::byte*)indices, IT_16Bit, std::size(indices));
+	}
+
+	return { &mRenderObject, 1 };
 }
 
 BuildingObject::BuildingObject(GameWorld* world)