LibGL: Implement glOrtho and underlying functions

5 files changed, 43 insertions, 0 deletions

diff --git a/Userland/Libraries/LibGL/GL/gl.h b/Userland/Libraries/LibGL/GL/gl.h
index 76f67d7005..7de99d5aeb 100644
--- a/Userland/Libraries/LibGL/GL/gl.h
+++ b/Userland/Libraries/LibGL/GL/gl.h
@@ -81,6 +81,7 @@ GLAPI GLubyte* glGetString(GLenum name);
 GLAPI void glLoadIdentity();
 GLAPI void glLoadMatrixf(const GLfloat* matrix);
 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 glRotatef(GLfloat angle, GLfloat x, GLfloat y, GLfloat z);
diff --git a/Userland/Libraries/LibGL/GLContext.h b/Userland/Libraries/LibGL/GLContext.h
index 4d6f02a4a2..dc7f75288c 100644
--- a/Userland/Libraries/LibGL/GLContext.h
+++ b/Userland/Libraries/LibGL/GLContext.h
@@ -28,6 +28,7 @@ public:
     virtual void gl_load_identity() = 0;
     virtual void gl_load_matrix(const FloatMatrix4x4& matrix) = 0;
     virtual void gl_matrix_mode(GLenum mode) = 0;
+    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_rotate(GLdouble angle, GLdouble x, GLdouble y, GLdouble z) = 0;
diff --git a/Userland/Libraries/LibGL/GLMat.cpp b/Userland/Libraries/LibGL/GLMat.cpp
index 7b0bde969f..a80a54990b 100644
--- a/Userland/Libraries/LibGL/GLMat.cpp
+++ b/Userland/Libraries/LibGL/GLMat.cpp
@@ -65,3 +65,8 @@ void glFrustum(GLdouble left, GLdouble right, GLdouble bottom, GLdouble top, GLd
 {
     g_gl_context->gl_frustum(left, right, bottom, top, nearVal, farVal);
 }
+
+void glOrtho(GLdouble left, GLdouble right, GLdouble bottom, GLdouble top, GLdouble nearVal, GLdouble farVal)
+{
+    g_gl_context->gl_ortho(left, right, bottom, top, nearVal, farVal);
+}
diff --git a/Userland/Libraries/LibGL/SoftwareGLContext.cpp b/Userland/Libraries/LibGL/SoftwareGLContext.cpp
index 3dc67eb8cd..514ce2f126 100644
--- a/Userland/Libraries/LibGL/SoftwareGLContext.cpp
+++ b/Userland/Libraries/LibGL/SoftwareGLContext.cpp
@@ -445,6 +445,41 @@ void SoftwareGLContext::gl_frustum(GLdouble left, GLdouble right, GLdouble botto
     m_error = GL_NO_ERROR;
 }
 
+void SoftwareGLContext::gl_ortho(GLdouble left, GLdouble right, GLdouble bottom, GLdouble top, GLdouble near_val, GLdouble far_val)
+{
+    if (m_in_draw_state) {
+        m_error = GL_INVALID_OPERATION;
+        return;
+    }
+
+    if (left == right || bottom == top || near_val == far_val) {
+        m_error = GL_INVALID_VALUE;
+        return;
+    }
+
+    auto rl = right - left;
+    auto tb = top - bottom;
+    auto fn = far_val - near_val;
+    auto tx = -(right + left) / rl;
+    auto ty = -(top + bottom) / tb;
+    auto tz = -(far_val + near_val) / fn;
+
+    FloatMatrix4x4 projection {
+        static_cast<float>(2 / rl), 0, 0, static_cast<float>(tx),
+        0, static_cast<float>(2 / tb), 0, static_cast<float>(ty),
+        0, 0, static_cast<float>(-2 / fn), static_cast<float>(tz),
+        0, 0, 0, 1
+    };
+
+    if (m_current_matrix_mode == GL_PROJECTION) {
+        m_projection_matrix = m_projection_matrix * projection;
+    } else if (m_current_matrix_mode == GL_MODELVIEW) {
+        m_projection_matrix = m_model_view_matrix * projection;
+    }
+
+    m_error = GL_NO_ERROR;
+}
+
 GLenum SoftwareGLContext::gl_get_error()
 {
     if (m_in_draw_state) {
diff --git a/Userland/Libraries/LibGL/SoftwareGLContext.h b/Userland/Libraries/LibGL/SoftwareGLContext.h
index 54a0cea7a8..d1b9bca826 100644
--- a/Userland/Libraries/LibGL/SoftwareGLContext.h
+++ b/Userland/Libraries/LibGL/SoftwareGLContext.h
@@ -27,6 +27,7 @@ public:
     virtual void gl_load_identity() override;
     virtual void gl_load_matrix(const FloatMatrix4x4& matrix) override;
     virtual void gl_matrix_mode(GLenum mode) override;
+    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_rotate(GLdouble angle, GLdouble x, GLdouble y, GLdouble z) override;