GPU: Implement line rendering

src/pse/gpu.cpp

@@ -580,7 +580,8 @@ bool GPU::HandleRenderCommand()
         // polyline goes until we hit the termination code
         num_vertices = 0;
         bool found_terminator = false;
-        for (size_t pos = 0; pos < m_GP0_command.size(); pos += words_per_vertex)
+        for (u32 pos = BoolToUInt32(!rc.shading_enable); pos < static_cast<u32>(m_GP0_command.size());
+             pos += words_per_vertex)
         {
           if (m_GP0_command[pos] == 0x55555555)
           {

src/pse/gpu.h

@@ -151,8 +151,8 @@ protected:
     BitField<u32, u32, 0, 11> x_s11;
     BitField<u32, u32, 16, 11> y_s11;
 
-    u32 x() const { return S11ToS32(x_s11); }
+    s32 x() const { return S11ToS32(x_s11); }
-    u32 y() const { return S11ToS32(y_s11); }
+    s32 y() const { return S11ToS32(y_s11); }
   };
 
   void SoftReset();

src/pse/gpu_hw.cpp

@@ -111,6 +111,26 @@ void GPU_HW::LoadVertices(RenderCommand rc, u32 num_vertices)
     }
     break;
 
+    case Primitive::Line:
+    {
+      const u32 first_color = rc.color_for_first_vertex;
+      const bool shaded = rc.shading_enable;
+
+      u32 buffer_pos = 1;
+      for (u32 i = 0; i < num_vertices; i++)
+      {
+        // x/y are encoded differently for lines - 16 bits each
+        const u32 color = (shaded && i > 0) ? (m_GP0_command[buffer_pos++] & UINT32_C(0x00FFFFFF)) : first_color;
+        const s32 x = Truncate16(m_GP0_command[buffer_pos]);
+        const s32 y = Truncate16(m_GP0_command[buffer_pos++] >> 16);
+        m_batch.vertices.push_back(HWVertex{x, y, color});
+      }
+
+      FlushRender();
+      UpdateDisplay();
+    }
+    break;
+
     default:
       UnreachableCode();
       break;
@@ -357,7 +377,7 @@ void main()
 GPU_HW::HWRenderBatch::Primitive GPU_HW::GetPrimitiveForCommand(RenderCommand rc)
 {
   if (rc.primitive == Primitive::Line)
-    return HWRenderBatch::Primitive::Lines;
+    return rc.polyline ? HWRenderBatch::Primitive::LineStrip : HWRenderBatch::Primitive::Lines;
   else if ((rc.primitive == Primitive::Polygon && rc.quad_polygon) || rc.primitive == Primitive::Rectangle)
     return HWRenderBatch::Primitive::TriangleStrip;
   else
@@ -395,9 +415,9 @@ void GPU_HW::DispatchRenderCommand(RenderCommand rc, u32 num_vertices)
   }
 
   // has any state changed which requires a new batch?
-  const bool rc_transparency_enable = rc.transparency_enable;
+  const bool rc_transparency_enable = rc.IsTransparencyEnabled();
-  const bool rc_texture_enable = rc.texture_enable;
+  const bool rc_texture_enable = rc.IsTextureEnabled();
-  const bool rc_texture_blend_enable = !rc.texture_blend_disable;
+  const bool rc_texture_blend_enable = rc.IsTextureBlendingEnabled();
   const HWRenderBatch::Primitive rc_primitive = GetPrimitiveForCommand(rc);
   const u32 max_added_vertices = num_vertices + 2;
   const bool buffer_overflow = (m_batch.vertices.size() + max_added_vertices) >= MAX_BATCH_VERTEX_COUNT;
@@ -405,9 +425,10 @@ void GPU_HW::DispatchRenderCommand(RenderCommand rc, u32 num_vertices)
     m_batch.render_command_bits != rc.bits && m_batch.transparency_enable != rc_transparency_enable ||
     m_batch.texture_enable != rc_texture_enable || m_batch.texture_blending_enable != rc_texture_blend_enable ||
     m_batch.primitive != rc_primitive;
+  const bool restart_line_strip = (rc_primitive == HWRenderBatch::Primitive::LineStrip);
   const bool needs_flush =
     !IsFlushed() && (m_render_state.IsTextureColorModeChanged() || m_render_state.IsTransparencyModeChanged() ||
-                     buffer_overflow || rc_changed);
+                     buffer_overflow || rc_changed || restart_line_strip);
   if (needs_flush)
     FlushRender();
 

src/pse/gpu_hw.h

@@ -32,8 +32,9 @@ protected:
     enum class Primitive : u8
     {
       Lines = 0,
-      Triangles = 1,
+      LineStrip = 1,
-      TriangleStrip = 2
+      Triangles = 2,
+      TriangleStrip = 3
     };
 
     u32 render_command_bits;

src/pse/gpu_hw_opengl.cpp

@@ -441,7 +441,7 @@ void GPU_HW_OpenGL::FlushRender()
   glBufferSubData(GL_ARRAY_BUFFER, 0, static_cast<GLsizei>(sizeof(HWVertex) * m_batch.vertices.size()),
                   m_batch.vertices.data());
 
-  static constexpr std::array<GLenum, 3> gl_primitives = {{GL_LINES, GL_TRIANGLES, GL_TRIANGLE_STRIP}};
+  static constexpr std::array<GLenum, 4> gl_primitives = {{GL_LINES, GL_LINE_STRIP, GL_TRIANGLES, GL_TRIANGLE_STRIP}};
   glDrawArrays(gl_primitives[static_cast<u8>(m_batch.primitive)], 0, static_cast<GLsizei>(m_batch.vertices.size()));
 
   m_batch.vertices.clear();