From 65b8d8f91e820f910d6c096b153438157c0795b9 Mon Sep 17 00:00:00 2001
From: Joshua Goins <josh@redstrate.com>
Date: Tue, 3 Jun 2025 05:24:24 -0400
Subject: [PATCH] Fix perspective/view matrices in Dawntrail renderer

After staring at Renderdoc for a while, I finally figured out the magic
combination to make this work. For static models, we need a new constant
buffer for the view(?) matrix.
---
 renderer/include/gamerenderer.h  |  1 +
 renderer/include/shaderstructs.h |  8 ++++++++
 renderer/src/gamerenderer.cpp    | 18 ++++++++++++++++--
 3 files changed, 25 insertions(+), 2 deletions(-)

diff --git a/renderer/include/gamerenderer.h b/renderer/include/gamerenderer.h
index f0e7cc2..be19efb 100644
--- a/renderer/include/gamerenderer.h
+++ b/renderer/include/gamerenderer.h
@@ -103,6 +103,7 @@ private:
     Buffer g_AmbientParam;
     Buffer g_ShaderTypeParameter;
     Buffer g_PbrParameterCommon;
+    Buffer g_WorldViewMatrix;
 
     Buffer m_planeVertexBuffer;
 
diff --git a/renderer/include/shaderstructs.h b/renderer/include/shaderstructs.h
index 055f48b..1448001 100644
--- a/renderer/include/shaderstructs.h
+++ b/renderer/include/shaderstructs.h
@@ -114,3 +114,11 @@ struct ShaderTypeParameter {
 struct PbrParameterCommon {
     glm::vec4 unk;
 };
+
+// Dawntrail
+// Only found in static models, not skinned ones?
+struct WorldViewMatrix {
+    glm::mat4 m_WorldViewMatrix;
+    glm::vec4 m_EyePosition;
+    glm::vec4 m_Unk;
+};
diff --git a/renderer/src/gamerenderer.cpp b/renderer/src/gamerenderer.cpp
index 370ddd9..01b82aa 100644
--- a/renderer/src/gamerenderer.cpp
+++ b/renderer/src/gamerenderer.cpp
@@ -242,6 +242,12 @@ GameRenderer::GameRenderer(Device &device, GameData *data)
         m_device.copyToBuffer(g_PbrParameterCommon, &pbrParameterCommon, sizeof(PbrParameterCommon));
     }
 
+    // worldViewMatrix
+    if (m_dawntrailMode) {
+        g_WorldViewMatrix = m_device.createBuffer(sizeof(WorldViewMatrix), VK_BUFFER_USAGE_UNIFORM_BUFFER_BIT);
+        m_device.nameBuffer(g_WorldViewMatrix, "g_WorldViewMatrix");
+    }
+
     VkSamplerCreateInfo samplerInfo = {};
     samplerInfo.sType = VK_STRUCTURE_TYPE_SAMPLER_CREATE_INFO;
     samplerInfo.magFilter = VK_FILTER_NEAREST;
@@ -276,7 +282,7 @@ void GameRenderer::render(VkCommandBuffer commandBuffer, Camera &camera, Scene &
     const glm::mat4 viewProjectionMatrix = camera.perspective * camera.view;
 
     // unknown
-    cameraParameter.m_unknownMatrix = glm::transpose(glm::inverse(camera.view));
+    cameraParameter.m_unknownMatrix = glm::transpose(camera.perspective);
 
     cameraParameter.m_ViewMatrix = glm::transpose(camera.view);
     cameraParameter.m_InverseViewMatrix = cameraParameter.m_unknownMatrix;
@@ -287,12 +293,18 @@ void GameRenderer::render(VkCommandBuffer commandBuffer, Camera &camera, Scene &
     cameraParameter.m_InverseProjectionMatrix = glm::transpose(glm::inverse(viewProjectionMatrix));
     cameraParameter.m_ProjectionMatrix = glm::transpose(viewProjectionMatrix);
 
-    cameraParameter.m_MainViewToProjectionMatrix = glm::transpose(glm::inverse(camera.perspective));
+    cameraParameter.m_MainViewToProjectionMatrix = glm::transpose(camera.perspective);
     cameraParameter.m_EyePosition = glm::vec4(camera.position, 0.0f);
     cameraParameter.m_LookAtVector = glm::vec4(0.0f); // placeholder
 
     m_device.copyToBuffer(g_CameraParameter, &cameraParameter, sizeof(CameraParameter));
 
+    WorldViewMatrix worldViewMatrix;
+    worldViewMatrix.m_WorldViewMatrix = cameraParameter.m_ViewMatrix;
+    worldViewMatrix.m_EyePosition = glm::vec4(camera.position, 0.0f);
+
+    m_device.copyToBuffer(g_WorldViewMatrix, &worldViewMatrix, sizeof(WorldViewMatrix));
+
     int i = 0;
     for (const auto &pass : passes) {
         // hardcoded to the known pass for now
@@ -1412,6 +1424,8 @@ GameRenderer::createDescriptorFor(const DrawObject *object, const CachedPipeline
                         useUniformBuffer(g_ShaderTypeParameter);
                     } else if (strcmp(name, "g_PbrParameterCommon") == 0) {
                         useUniformBuffer(g_PbrParameterCommon);
+                    } else if (strcmp(name, "g_WorldViewMatrix") == 0) {
+                        useUniformBuffer(g_WorldViewMatrix);
                     } else {
                         qInfo() << "Unknown resource:" << name;
                         info->buffer = m_dummyBuffer.buffer;