LibGL: Implement `glClearStencil`

Userland/Libraries/LibGL/GL/gl.h

@@ -51,6 +51,7 @@ extern "C" {
 
 // Buffer bits
 #define GL_DEPTH_BUFFER_BIT 0x00100
+#define GL_STENCIL_BUFFER_BIT 0x00400
 #define GL_COLOR_BUFFER_BIT 0x04000
 
 // Enable capabilities
@@ -349,6 +350,7 @@ GLAPI void glBegin(GLenum mode);
 GLAPI void glClear(GLbitfield mask);
 GLAPI void glClearColor(GLclampf red, GLclampf green, GLclampf blue, GLclampf alpha);
 GLAPI void glClearDepth(GLdouble depth);
+GLAPI void glClearStencil(GLint s);
 GLAPI void glColor3f(GLfloat r, GLfloat g, GLfloat b);
 GLAPI void glColor3fv(const GLfloat* v);
 GLAPI void glColor3ub(GLubyte r, GLubyte g, GLubyte b);

Userland/Libraries/LibGL/GLContext.h

@@ -22,6 +22,7 @@ public:
     virtual void gl_clear(GLbitfield mask) = 0;
     virtual void gl_clear_color(GLclampf red, GLclampf green, GLclampf blue, GLclampf alpha) = 0;
     virtual void gl_clear_depth(GLdouble depth) = 0;
+    virtual void gl_clear_stencil(GLint s) = 0;
     virtual void gl_color(GLdouble r, GLdouble g, GLdouble b, GLdouble a) = 0;
     virtual void gl_delete_textures(GLsizei n, const GLuint* textures) = 0;
     virtual void gl_end() = 0;

Userland/Libraries/LibGL/GLStencil.cpp

@@ -9,6 +9,11 @@
 
 extern GL::GLContext* g_gl_context;
 
+void glClearStencil(GLint s)
+{
+    g_gl_context->gl_clear_stencil(s);
+}
+
 void glStencilFunc(GLenum func, GLint ref, GLuint mask)
 {
     g_gl_context->gl_stencil_func_separate(GL_FRONT_AND_BACK, func, ref, mask);

Userland/Libraries/LibGL/SoftwareGLContext.cpp

@@ -84,6 +84,8 @@ void SoftwareGLContext::gl_clear(GLbitfield mask)
 
     if (mask & GL_DEPTH_BUFFER_BIT)
         m_rasterizer.clear_depth(static_cast<float>(m_clear_depth));
+
+    // FIXME: implement GL_STENCIL_BUFFER_BIT
 }
 
 void SoftwareGLContext::gl_clear_color(GLclampf red, GLclampf green, GLclampf blue, GLclampf alpha)
@@ -104,6 +106,17 @@ void SoftwareGLContext::gl_clear_depth(GLdouble depth)
     m_clear_depth = depth;
 }
 
+void SoftwareGLContext::gl_clear_stencil(GLint s)
+{
+    APPEND_TO_CALL_LIST_AND_RETURN_IF_NEEDED(gl_clear_stencil, s);
+
+    RETURN_WITH_ERROR_IF(m_in_draw_state, GL_INVALID_OPERATION);
+
+    // FIXME: "s is masked with 2^m - 1 , where m is the number of bits in the stencil buffer"
+
+    m_clear_stencil = s;
+}
+
 void SoftwareGLContext::gl_color(GLdouble r, GLdouble g, GLdouble b, GLdouble a)
 {
     APPEND_TO_CALL_LIST_AND_RETURN_IF_NEEDED(gl_color, r, g, b, a);

Userland/Libraries/LibGL/SoftwareGLContext.h

@@ -33,6 +33,7 @@ public:
     virtual void gl_clear(GLbitfield mask) override;
     virtual void gl_clear_color(GLclampf red, GLclampf green, GLclampf blue, GLclampf alpha) override;
     virtual void gl_clear_depth(GLdouble depth) override;
+    virtual void gl_clear_stencil(GLint s) override;
     virtual void gl_color(GLdouble r, GLdouble g, GLdouble b, GLdouble a) override;
     virtual void gl_delete_textures(GLsizei n, const GLuint* textures) override;
     virtual void gl_end() override;
@@ -142,8 +143,10 @@ private:
     Vector<FloatMatrix4x4> m_projection_matrix_stack;
     Vector<FloatMatrix4x4> m_model_view_matrix_stack;
 
-    FloatVector4 m_clear_color = { 0.0f, 0.0f, 0.0f, 0.0f };
-    double m_clear_depth = { 1.0 };
+    FloatVector4 m_clear_color { 0.0f, 0.0f, 0.0f, 0.0f };
+    double m_clear_depth { 1.0 };
+    GLint m_clear_stencil { 0 };
+
     FloatVector4 m_current_vertex_color = { 1.0f, 1.0f, 1.0f, 1.0f };
     FloatVector4 m_current_vertex_tex_coord = { 0.0f, 0.0f, 0.0f, 0.0f };
     FloatVector3 m_current_vertex_normal = { 0.0f, 0.0f, 1.0f };
@@ -236,6 +239,7 @@ private:
             decltype(&SoftwareGLContext::gl_clear),
             decltype(&SoftwareGLContext::gl_clear_color),
             decltype(&SoftwareGLContext::gl_clear_depth),
+            decltype(&SoftwareGLContext::gl_clear_stencil),
             decltype(&SoftwareGLContext::gl_color),
             decltype(&SoftwareGLContext::gl_end),
             decltype(&SoftwareGLContext::gl_frustum),