LibGL: Implement glGetProgramiv

Author: https://github.com/sunverwerth
Commit: https://github.com/SerenityOS/serenity/commit/1b7b6e6c91
Pull-request: https://github.com/SerenityOS/serenity/pull/16225
Reviewed-by: https://github.com/ADKaster ✅
Reviewed-by: https://github.com/gmta ✅
Reviewed-by: https://github.com/supercomputer7

Userland/Libraries/LibGL/GL/gl.h

@@ -606,6 +606,7 @@ extern "C" {
 #define GL_SHADER_TYPE 0x8B4F
 #define GL_DELETE_STATUS 0x8B80
 #define GL_COMPILE_STATUS 0x8B81
+#define GL_LINK_STATUS 0x8B82
 #define GL_INFO_LOG_LENGTH 0x8B84
 #define GL_SHADER_SOURCE_LENGTH 0x8B88
 
@@ -832,6 +833,7 @@ GLAPI void glDeleteProgram(GLuint program);
 GLAPI void glAttachShader(GLuint program, GLuint shader);
 GLAPI void glLinkProgram(GLuint program);
 GLAPI void glUseProgram(GLuint program);
+GLAPI void glGetProgramiv(GLuint program, GLenum pname, GLint* params);
 
 #ifdef __cplusplus
 }

Userland/Libraries/LibGL/GLAPI.cpp

@@ -499,6 +499,11 @@ void glGetMaterialiv(GLenum face, GLenum pname, GLint* params)
     g_gl_context->gl_get_material(face, pname, params, GL_INT);
 }
 
+void glGetProgramiv(GLuint program, GLenum pname, GLint* params)
+{
+    g_gl_context->gl_get_program(program, pname, params);
+}
+
 GLubyte const* glGetString(GLenum name)
 {
     return g_gl_context->gl_get_string(name);

Userland/Libraries/LibGL/GLContext.h

@@ -241,6 +241,7 @@ public:
     void gl_attach_shader(GLuint program, GLuint shader);
     void gl_link_program(GLuint program);
     void gl_use_program(GLuint program);
+    void gl_get_program(GLuint program, GLenum pname, GLint* params);
 
 private:
     void sync_device_config();

Userland/Libraries/LibGL/Shader.cpp

@@ -177,4 +177,39 @@ void GLContext::gl_use_program(GLuint program)
     m_current_program = it->value;
 }
 
+void GLContext::gl_get_program(GLuint program, GLenum pname, GLint* params)
+{
+    auto it = m_allocated_programs.find(program);
+
+    // FIXME: implement check "GL_INVALID_VALUE is generated if program is not a value generated by OpenGL."
+    RETURN_WITH_ERROR_IF(it == m_allocated_programs.end(), GL_INVALID_OPERATION);
+    // FIXME: implement check "GL_INVALID_OPERATION is generated if pname is GL_GEOMETRY_VERTICES_OUT, GL_GEOMETRY_INPUT_TYPE, or GL_GEOMETRY_OUTPUT_TYPE, and program does not contain a geometry shader."
+
+    // FIXME: implement all the other allowed pname values (https://registry.khronos.org/OpenGL-Refpages/gl4/html/glGetProgram.xhtml)
+    RETURN_WITH_ERROR_IF(pname != GL_DELETE_STATUS
+            && pname != GL_LINK_STATUS
+            && pname != GL_INFO_LOG_LENGTH,
+        GL_INVALID_ENUM);
+
+    // FIXME: implement check "GL_INVALID_OPERATION is generated if pname is GL_COMPUTE_WORK_GROUP_SIZE and program does not contain a binary for the compute shader stage."
+
+    switch (pname) {
+    case GL_DELETE_STATUS:
+        // FIXME: Return the actual delete status once we implement this missing feature
+        *params = GL_FALSE;
+        break;
+
+    case GL_LINK_STATUS:
+        *params = it->value->link_status() ? GL_TRUE : GL_FALSE;
+        break;
+
+    case GL_INFO_LOG_LENGTH:
+        *params = it->value->info_log_length();
+        break;
+
+    default:
+        VERIFY_NOT_REACHED();
+    }
+}
+
 }

Userland/Libraries/LibGL/Shaders/Program.cpp

@@ -54,4 +54,13 @@ ErrorOr<void> Program::link()
     return {};
 }
 
+size_t Program::info_log_length() const
+{
+    if (!m_info_log.has_value())
+        return 0;
+
+    // Per the spec we return the size including the null terminator
+    return m_info_log.value().bytes().size() + 1;
+}
+
 }

Userland/Libraries/LibGL/Shaders/Program.h

@@ -8,7 +8,9 @@
 
 #include <AK/Error.h>
 #include <AK/NonnullRefPtr.h>
+#include <AK/Optional.h>
 #include <AK/RefCounted.h>
+#include <AK/String.h>
 #include <AK/Vector.h>
 #include <LibGL/Shaders/Shader.h>
 
@@ -22,11 +24,13 @@ public:
     ErrorOr<void> attach_shader(Shader&);
     ErrorOr<void> link();
     bool link_status() const { return m_link_status; }
+    size_t info_log_length() const;
 
 private:
     bool m_link_status { false };
     Vector<NonnullRefPtr<Shader>> m_vertex_shaders;
     Vector<NonnullRefPtr<Shader>> m_fragment_shaders;
+    Optional<String> m_info_log;
 };
 
 }