60 lines
2.0 KiB
C
60 lines
2.0 KiB
C
/* ************************************************************************** */
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/* */
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/* ::: :::::::: */
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/* mat4_perspective.c :+: :+: :+: */
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/* +:+ +:+ +:+ */
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/* By: gbrochar <gbrochar@student.42.fr> +#+ +:+ +#+ */
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/* +#+#+#+#+#+ +#+ */
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/* Created: 2020/12/23 15:52:55 by gbrochar #+# #+# */
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/* Updated: 2020/12/23 16:11:07 by gbrochar ### ########.fr */
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/* */
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/* ************************************************************************** */
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#include "mat4.h"
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#include "vec4.h"
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t_mat4 mat4_frustrum(t_persp_tool tool, double near, double far)
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{
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double x;
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double y;
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t_vec4 tool2;
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t_mat4 frustrum;
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x = (2.0 * near) / (tool.xmax - tool.xmin);
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y = (2.0 * near) / (tool.ymax - tool.ymin);
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tool2.x = (tool.xmax + tool.xmin) / (tool.xmax - tool.xmin);
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tool2.y = (tool.ymax + tool.ymin) / (tool.ymax - tool.ymin);
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tool2.z = -(far + near) / (far - near);
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tool2.w = (-2.0 * far * near) / (far - near);
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frustrum.data[0] = x;
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frustrum.data[4] = 0;
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frustrum.data[8] = tool2.x;
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frustrum.data[12] = 0;
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frustrum.data[1] = 0;
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frustrum.data[5] = y;
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frustrum.data[9] = tool2.y;
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frustrum.data[13] = 0;
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frustrum.data[2] = 0;
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frustrum.data[6] = 0;
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frustrum.data[10] = tool2.z;
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frustrum.data[14] = tool2.w;
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frustrum.data[3] = 0;
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frustrum.data[7] = 0;
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frustrum.data[11] = -1;
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frustrum.data[15] = 0;
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return frustrum;
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}
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t_mat4 mat4_perspective(
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double fov, double aspect, double near, double far)
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{
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t_persp_tool tool;
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tool.ymax = near * tan(fov / 2.0);
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tool.ymin = -tool.ymax;
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tool.xmin = tool.ymin * aspect;
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tool.xmax = tool.ymax * aspect;
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return mat4_frustrum(tool, near, far);
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}
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