LibGL: Implement `glMultMatrixf`

5 files changed, 48 insertions, 13 deletions

diff --git a/Userland/Libraries/LibGL/GL/gl.h b/Userland/Libraries/LibGL/GL/gl.h
index 0a2cf84ad6..36646ae92a 100644
--- a/Userland/Libraries/LibGL/GL/gl.h
+++ b/Userland/Libraries/LibGL/GL/gl.h
@@ -351,6 +351,7 @@ GLAPI void glMatrixMode(GLenum mode);
 GLAPI void glOrtho(GLdouble left, GLdouble right, GLdouble bottom, GLdouble top, GLdouble nearVal, GLdouble farVal);
 GLAPI void glPushMatrix();
 GLAPI void glPopMatrix();
+GLAPI void glMultMatrixf(GLfloat const* matrix);
 GLAPI void glRotatef(GLfloat angle, GLfloat x, GLfloat y, GLfloat z);
 GLAPI void glScalef(GLfloat x, GLfloat y, GLfloat z);
 GLAPI void glTranslatef(GLfloat x, GLfloat y, GLfloat z);
diff --git a/Userland/Libraries/LibGL/GLContext.h b/Userland/Libraries/LibGL/GLContext.h
index ddd7d9e296..a2ffa0989f 100644
--- a/Userland/Libraries/LibGL/GLContext.h
+++ b/Userland/Libraries/LibGL/GLContext.h
@@ -35,6 +35,7 @@ public:
     virtual void gl_ortho(GLdouble left, GLdouble right, GLdouble bottom, GLdouble top, GLdouble near_val, GLdouble far_val) = 0;
     virtual void gl_push_matrix() = 0;
     virtual void gl_pop_matrix() = 0;
+    virtual void gl_mult_matrix(FloatMatrix4x4 const& matrix) = 0;
     virtual void gl_rotate(GLdouble angle, GLdouble x, GLdouble y, GLdouble z) = 0;
     virtual void gl_scale(GLdouble x, GLdouble y, GLdouble z) = 0;
     virtual void gl_translate(GLdouble x, GLdouble y, GLdouble z) = 0;
diff --git a/Userland/Libraries/LibGL/GLMat.cpp b/Userland/Libraries/LibGL/GLMat.cpp
index 8c3fa0c548..c459f71e07 100644
--- a/Userland/Libraries/LibGL/GLMat.cpp
+++ b/Userland/Libraries/LibGL/GLMat.cpp
@@ -35,18 +35,28 @@ void glPopMatrix()
     g_gl_context->gl_pop_matrix();
 }
 
-void glLoadMatrixf(const GLfloat* matrix)
+/*
+ * Transposes input matrices (column-major) to our Matrix (row-major).
+ */
+template<typename T>
+static constexpr Matrix4x4<T> transpose_input_matrix(T const* matrix)
 {
-    // Transpose the matrix here because glLoadMatrix expects elements
-    // in column major order but out Matrix class stores elements in
-    // row major order.
-    FloatMatrix4x4 mat(
+    return {
         matrix[0], matrix[4], matrix[8], matrix[12],
         matrix[1], matrix[5], matrix[9], matrix[13],
         matrix[2], matrix[6], matrix[10], matrix[14],
-        matrix[3], matrix[7], matrix[11], matrix[15]);
+        matrix[3], matrix[7], matrix[11], matrix[15],
+    };
+}
 
-    g_gl_context->gl_load_matrix(mat);
+void glMultMatrixf(GLfloat const* matrix)
+{
+    g_gl_context->gl_mult_matrix(transpose_input_matrix<float>(matrix));
+}
+
+void glLoadMatrixf(const GLfloat* matrix)
+{
+    g_gl_context->gl_load_matrix(transpose_input_matrix<float>(matrix));
 }
 
 void glLoadIdentity()
diff --git a/Userland/Libraries/LibGL/SoftwareGLContext.cpp b/Userland/Libraries/LibGL/SoftwareGLContext.cpp
index 495e29401c..2af62ab289 100644
--- a/Userland/Libraries/LibGL/SoftwareGLContext.cpp
+++ b/Userland/Libraries/LibGL/SoftwareGLContext.cpp
@@ -33,6 +33,14 @@ static constexpr size_t MATRIX_STACK_LIMIT = 1024;
             return;                                               \
     }
 
+#define APPEND_TO_CALL_LIST_WITH_ARG_AND_RETURN_IF_NEEDED(name, arg) \
+    if (should_append_to_listing()) {                                \
+        auto ptr = store_in_listing(arg);                            \
+        append_to_listing<&SoftwareGLContext::name>(*ptr);           \
+        if (!should_execute_after_appending_to_listing())            \
+            return;                                                  \
+    }
+
 #define RETURN_WITH_ERROR_IF(condition, error) \
     if (condition) {                           \
         if (m_error == GL_NO_ERROR)            \
@@ -368,12 +376,7 @@ void SoftwareGLContext::gl_load_identity()
 
 void SoftwareGLContext::gl_load_matrix(const FloatMatrix4x4& matrix)
 {
-    if (should_append_to_listing()) {
-        auto ptr = store_in_listing(matrix);
-        append_to_listing<&SoftwareGLContext::gl_load_matrix>(*ptr);
-        if (!should_execute_after_appending_to_listing())
-            return;
-    }
+    APPEND_TO_CALL_LIST_WITH_ARG_AND_RETURN_IF_NEEDED(gl_load_matrix, matrix);
 
     RETURN_WITH_ERROR_IF(m_in_draw_state, GL_INVALID_OPERATION);
 
@@ -442,6 +445,24 @@ void SoftwareGLContext::gl_pop_matrix()
     }
 }
 
+void SoftwareGLContext::gl_mult_matrix(FloatMatrix4x4 const& matrix)
+{
+    APPEND_TO_CALL_LIST_WITH_ARG_AND_RETURN_IF_NEEDED(gl_mult_matrix, matrix);
+
+    RETURN_WITH_ERROR_IF(m_in_draw_state, GL_INVALID_OPERATION);
+
+    switch (m_current_matrix_mode) {
+    case GL_PROJECTION:
+        m_projection_matrix = m_projection_matrix * matrix;
+        break;
+    case GL_MODELVIEW:
+        m_model_view_matrix = m_model_view_matrix * matrix;
+        break;
+    default:
+        dbgln_if(GL_DEBUG, "glMultMatrix(): Attempt to mult matrix with unsupported matrix mode {}", m_current_matrix_mode);
+    }
+}
+
 void SoftwareGLContext::gl_rotate(GLdouble angle, GLdouble x, GLdouble y, GLdouble z)
 {
     APPEND_TO_CALL_LIST_AND_RETURN_IF_NEEDED(gl_rotate, angle, x, y, z);
diff --git a/Userland/Libraries/LibGL/SoftwareGLContext.h b/Userland/Libraries/LibGL/SoftwareGLContext.h
index c95a125a1b..611e0298fd 100644
--- a/Userland/Libraries/LibGL/SoftwareGLContext.h
+++ b/Userland/Libraries/LibGL/SoftwareGLContext.h
@@ -46,6 +46,7 @@ public:
     virtual void gl_ortho(GLdouble left, GLdouble right, GLdouble bottom, GLdouble top, GLdouble near_val, GLdouble far_val) override;
     virtual void gl_push_matrix() override;
     virtual void gl_pop_matrix() override;
+    virtual void gl_mult_matrix(FloatMatrix4x4 const& matrix) override;
     virtual void gl_rotate(GLdouble angle, GLdouble x, GLdouble y, GLdouble z) override;
     virtual void gl_scale(GLdouble x, GLdouble y, GLdouble z) override;
     virtual void gl_translate(GLdouble x, GLdouble y, GLdouble z) override;
@@ -216,6 +217,7 @@ private:
             decltype(&SoftwareGLContext::gl_ortho),
             decltype(&SoftwareGLContext::gl_push_matrix),
             decltype(&SoftwareGLContext::gl_pop_matrix),
+            decltype(&SoftwareGLContext::gl_mult_matrix),
             decltype(&SoftwareGLContext::gl_rotate),
             decltype(&SoftwareGLContext::gl_scale),
             decltype(&SoftwareGLContext::gl_translate),