Make the NDS teardown more robust (#1798)

* Make cleanup a little more robust to mitigate undefined behavior

- Add some null checks before cleaning up the GPU3D renderer
- Make sure that all deleted objects are null
- Move cleanup logic out of an assert call
- Note that deleting a null pointer is a no-op, so there's no need to check for null beforehand
- Use RAII for GLCompositor instead of Init/DeInit methods

* Replace a DeInit call that I missed

* Make ARMJIT_Memory less likely to generate errors

- Set FastMem7/9Start to nullptr at the end
- Only close and unmap the file if it's initialized

* Make Renderer3D manage its resources with RAII

* Don't try to deallocate frontend resources that aren't loaded

* Make ARMJIT_Memory::DeInit more robust on the Switch

* Reset MemoryFile on Windows to INVALID_HANDLE_VALUE, not nullptr

- There is a difference

* Don't explicitly store a Valid state in GLCompositor or the 3D renderers

- Instead, create them with static methods while making the actual constructors private

* Make initialization of OpenGL resources fail if OpenGL isn't loaded

* assert that OpenGL is loaded instead of returning failure

1 files changed, 20 insertions, 2 deletions

diff --git a/src/OpenGLSupport.cpp b/src/OpenGLSupport.cpp
index 958930d..f1914fc 100644
--- a/src/OpenGLSupport.cpp
+++ b/src/OpenGLSupport.cpp
@@ -29,6 +29,12 @@ bool BuildShaderProgram(const char* vs, const char* fs, GLuint* ids, const char*
     int len;
     int res;
 
+    if (!glCreateShader)
+    {
+        Log(LogLevel::Error, "OpenGL: Cannot build shader program, OpenGL hasn't been loaded\n");
+        return false;
+    }
+
     ids[0] = glCreateShader(GL_VERTEX_SHADER);
     len = strlen(vs);
     glShaderSource(ids[0], 1, &vs, &len);
@@ -87,6 +93,12 @@ bool LinkShaderProgram(GLuint* ids)
 {
     int res;
 
+    if (!glLinkProgram)
+    {
+        Log(LogLevel::Error, "OpenGL: Cannot link shader program, OpenGL hasn't been loaded\n");
+        return false;
+    }
+
     glLinkProgram(ids[2]);
 
     glDetachShader(ids[2], ids[0]);
@@ -115,12 +127,18 @@ bool LinkShaderProgram(GLuint* ids)
 
 void DeleteShaderProgram(GLuint* ids)
 {
-    glDeleteProgram(ids[2]);
+    if (glDeleteProgram)
+    { // If OpenGL isn't loaded, then there's no shader program to delete
+        glDeleteProgram(ids[2]);
+    }
 }
 
 void UseShaderProgram(GLuint* ids)
 {
-    glUseProgram(ids[2]);
+    if (glUseProgram)
+    { // If OpenGL isn't loaded, then there's no shader program to use
+        glUseProgram(ids[2]);
+    }
 }
 
 }