GLORTHO(3G)

💖 GLORTHO (3G) 💖

okay so bestie, welcome to the glOrtho page, manual section 3G — this is the one that does the parallel projection thing and she is iconic, no cap ✨

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✨ NAME ✨

glOrtho — multiply the current matrix with an orthographic matrix 💅

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🎀 C SPECIFICATION 🎀

void glOrtho( GLdouble left,
              GLdouble right,
              GLdouble bottom,
              GLdouble top,
              GLdouble near_val,
              GLdouble far_val )

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🌸 PARAMETERS 🌸

• left, right — the coordinates for the left and right vertical clipping planes, respectively. your two side walls, basically 🧚
• bottom, top — the coordinates for the bottom and top horizontal clipping planes. your floor and your ceiling 🫶
• near_val, far_val — the distances to the nearer and farther depth clipping planes. heads up: these values are negative if the plane is gonna sit behind the viewer 👀

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💜 DESCRIPTION 💜

glOrtho describes a transformation that produces a parallel projection. the current matrix (go peek at glMatrixMode if you don't know which one that is) gets multiplied by this matrix, and the result replaces the current matrix — exactly as if glMultMatrix had been called with the following matrix as its argument:

       __________      0             0        tx
       0      __________         0        ty
       0          0      ________________ tz
       0          0             0         1

where

              tx=−__________

              ty=−__________

              tz=−________________

typically the matrix mode is GL_PROJECTION, and (left, bottom, -near_val) and (right, top, -near_val) specify the points on the near clipping plane that get mapped to the lower left and upper right corners of the window respectively — all assuming the eye is chilling at (0, 0, 0) 👁️ and -far_val specifies the location of the far clipping plane. also, both near_val and far_val can be either positive or negative, she contains multitudes 💫

use glPushMatrix and glPopMatrix to save and restore the current matrix stack, bestie, that's your undo button 🎀

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💀 ERRORS 💀

GL_INVALID_OPERATION is generated if glOrtho is executed between the execution of glBegin and the corresponding execution of glEnd. like, read the room. don't do that. 🙈

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⭐ ASSOCIATED GETS ⭐

• glGet with argument GL_MATRIX_MODE
• glGet with argument GL_COLOR_MATRIX
• glGet with argument GL_MODELVIEW_MATRIX
• glGet with argument GL_PROJECTION_MATRIX
• glGet with argument GL_TEXTURE_MATRIX

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🌈 SEE ALSO 🌈

glFrustum(3G), glMatrixMode(3G), glMultMatrix(3G), glPushMatrix(3G), glViewport(3G)

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and that's the whole page, periodt 💅 this was GLORTHO(3G) — page name in the footer is literally just GLORTHO(3G) again, no version stamp, no date, nothing, she's mysterious like that 💖 go forth and project, bestie 🦋