LibGL: Implement glGetShaderiv

Author: https://github.com/sunverwerth
Commit: https://github.com/SerenityOS/serenity/commit/424e0a2792
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

Tests/LibGL/TestShaders.cpp

@@ -44,10 +44,16 @@ TEST_CASE(0001_program_creation)
     vertex_shader = glCreateShader(GL_VERTEX_SHADER);
     glShaderSource(vertex_shader, 1, &vertex_shader_source, nullptr);
     glCompileShader(vertex_shader);
+    GLint vertex_shader_compile_status;
+    glGetShaderiv(vertex_shader, GL_COMPILE_STATUS, &vertex_shader_compile_status);
+    EXPECT_EQ(vertex_shader_compile_status, GL_TRUE);
 
     fragment_shader = glCreateShader(GL_FRAGMENT_SHADER);
     glShaderSource(fragment_shader, 1, &fragment_shader_source, nullptr);
     glCompileShader(fragment_shader);
+    GLint fragment_shader_compile_status;
+    glGetShaderiv(fragment_shader, GL_COMPILE_STATUS, &fragment_shader_compile_status);
+    EXPECT_EQ(fragment_shader_compile_status, GL_TRUE);
 
     program = glCreateProgram();
     glAttachShader(program, vertex_shader);

Userland/Libraries/LibGL/GL/gl.h

@@ -603,6 +603,11 @@ extern "C" {
 // Programmable pipeline
 #define GL_FRAGMENT_SHADER 0x8B30
 #define GL_VERTEX_SHADER 0x8B31
+#define GL_SHADER_TYPE 0x8B4F
+#define GL_DELETE_STATUS 0x8B80
+#define GL_COMPILE_STATUS 0x8B81
+#define GL_INFO_LOG_LENGTH 0x8B84
+#define GL_SHADER_SOURCE_LENGTH 0x8B88
 
 GLAPI void glBegin(GLenum mode);
 GLAPI void glClear(GLbitfield mask);
@@ -820,6 +825,7 @@ GLAPI GLuint glCreateShader(GLenum shader_type);
 GLAPI void glDeleteShader(GLuint shader);
 GLAPI void glShaderSource(GLuint shader, GLsizei count, GLchar const** string, GLint const* length);
 GLAPI void glCompileShader(GLuint shader);
+GLAPI void glGetShaderiv(GLuint shader, GLenum pname, GLint* params);
 
 GLAPI GLuint glCreateProgram();
 GLAPI void glDeleteProgram(GLuint program);

Userland/Libraries/LibGL/GLAPI.cpp

@@ -504,6 +504,11 @@ GLubyte const* glGetString(GLenum name)
     return g_gl_context->gl_get_string(name);
 }
 
+void glGetShaderiv(GLuint shader, GLenum pname, GLint* params)
+{
+    g_gl_context->gl_get_shader(shader, pname, params);
+}
+
 void glGetTexImage(GLenum target, GLint level, GLenum format, GLenum type, void* pixels)
 {
     g_gl_context->gl_get_tex_image(target, level, format, type, pixels);

Userland/Libraries/LibGL/GLContext.h

@@ -234,6 +234,7 @@ public:
     void gl_delete_shader(GLuint shader);
     void gl_shader_source(GLuint shader, GLsizei count, GLchar const** string, GLint const* length);
     void gl_compile_shader(GLuint shader);
+    void gl_get_shader(GLuint shader, GLenum pname, GLint* params);
 
     GLuint gl_create_program();
     void gl_delete_program(GLuint program);

Userland/Libraries/LibGL/Shader.cpp

@@ -70,6 +70,48 @@ void GLContext::gl_compile_shader(GLuint shader)
     (void)it->value->compile();
 }
 
+void GLContext::gl_get_shader(GLuint shader, GLenum pname, GLint* params)
+{
+    RETURN_WITH_ERROR_IF(pname != GL_SHADER_TYPE
+            && pname != GL_DELETE_STATUS
+            && pname != GL_COMPILE_STATUS
+            && pname != GL_INFO_LOG_LENGTH
+            && pname != GL_SHADER_SOURCE_LENGTH,
+        GL_INVALID_ENUM);
+
+    // FIXME: implement check "GL_INVALID_VALUE is generated if shader is not a value generated by OpenGL."
+    // FIXME: implement check "GL_INVALID_OPERATION is generated if pname is GL_COMPILE_STATUS, GL_INFO_LOG_LENGTH, or GL_SHADER_SOURCE_LENGTH but a shader compiler is not supported."
+
+    auto it = m_allocated_shaders.find(shader);
+    RETURN_WITH_ERROR_IF(it == m_allocated_shaders.end(), GL_INVALID_OPERATION);
+
+    switch (pname) {
+    case GL_SHADER_TYPE:
+        *params = it->value->type();
+        break;
+
+    case GL_DELETE_STATUS:
+        // FIXME: Return the actual delete status once we implement this missing feature
+        *params = GL_FALSE;
+        break;
+
+    case GL_COMPILE_STATUS:
+        *params = it->value->compile_status() ? GL_TRUE : GL_FALSE;
+        break;
+
+    case GL_INFO_LOG_LENGTH:
+        *params = it->value->info_log_length();
+        break;
+
+    case GL_SHADER_SOURCE_LENGTH:
+        *params = it->value->combined_source_length();
+        break;
+
+    default:
+        VERIFY_NOT_REACHED();
+    }
+}
+
 GLuint GLContext::gl_create_program()
 {
     GLuint program_name;

Userland/Libraries/LibGL/Shaders/Shader.cpp

@@ -28,4 +28,26 @@ ErrorOr<void> Shader::compile()
     return {};
 }
 
+size_t Shader::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;
+}
+
+size_t Shader::combined_source_length() const
+{
+    if (m_sources.is_empty())
+        return 0;
+
+    size_t combined_size = 0;
+    for (auto source : m_sources)
+        combined_size += source.bytes().size();
+
+    // Per the spec we return the size including the null terminator
+    return combined_size + 1;
+}
+
 }

Userland/Libraries/LibGL/Shaders/Shader.h

@@ -8,6 +8,7 @@
 
 #include <AK/Error.h>
 #include <AK/NonnullRefPtr.h>
+#include <AK/Optional.h>
 #include <AK/RefCounted.h>
 #include <AK/RefPtr.h>
 #include <AK/String.h>
@@ -27,6 +28,9 @@ public:
     GLenum type() const { return m_type; }
     bool compile_status() const { return m_compile_status; }
 
+    size_t info_log_length() const;
+    size_t combined_source_length() const;
+
 private:
     explicit Shader(GLenum shader_type)
         : m_type { shader_type }
@@ -36,6 +40,7 @@ private:
     Vector<String> m_sources;
     GLenum m_type;
     bool m_compile_status { false };
+    Optional<String> m_info_log;
 };
 
 }